In 1939, teacher Vera's looking for a summer job. Isaac, the recruiter at the agency, offers her a
position as an assistant for the Owens, commenting she was chosen specifically by them. Vera's wary
because she doesn't think she's suited for the position, but she changes her mind when she sees
the Owens even sent money in advance. Meanwhile Isaac's secretary is writing a bunch of invitation
letters for the guests that will be attending the Owens' special party. In another corner of
the city, a broadcaster is hired to record a few lines that supposedly will be used in a play. A
few days later, Vera is on the train on her way to her new job and can't help imagining a dangerous
rope hanging from the window. She gets even more uncomfortable when she realizes she's being stared
at by Philip, so she goes looking for a new place to sit and after walking by businessman William,
she ends up in the same cabin as Lawrence, a retired judge. On a road nearby, doctor Edward's
trying to drive responsibly but almost gets in an accident when he's passed by Anthony, who drives
like a maniac. A few hours later, all these people gather at the dock with General John to take a
boat to Soldier Island, where the party will be held. But when they get there, they're surprised
to discover the Owens haven't arrived. Butler Thomas and his wife Ethel explain the hosts will
be arriving later and introduce them to the final two guests that got here earlier on their own,
Anthony and Emily. The guests then proceed to get comfortable in their rooms. William takes some
notes about the others because somehow he already had a full list of everyone's names, Philip takes
a gun out of his suitcase that he hides on the night table, and Anthony has fun with an illegal
upper. The guests also discover that in every room of the house there's a framed poem called
"Ten Soldiers", which tells the story of ten men that got together to dine and died one by one
in different ways. Afterward, Vera takes a look around the house and ends up in the belowstairs,
only to be stopped by Ethel, who points out this area is staff only. Vera explains she was hired as
an assistant, but Ethel tells her the Owens left explicit instructions of treating her as a guest.
In the evening, dinner is announced with a gong, and the guests gather in the dining room where
they discover that in the middle of the table there are ten figurines to match the ten soldiers
from the poem. Dinner goes well will lots of conversation, yet the Owens still don't show up,
and Thomas explains there isn't a telephone to check on them. When the conversation touches on
the matter of cars, Edward realizes Anthony is the guy that ran him off the road, but Anthony
denies it and triggers an argument. The other guests quickly cut it off, making Anthony offer
a very fake apology. After dinner, the peace's interrupted when a strange voice coming from a
speaker proceeds to name all the guests to accuse them of murder, even mentioning the name of their
victims. All the guests are offended by this and demand an explanation, so Thomas takes them to the
room Vera saw earlier and reveals this had been a recording. At that moment, the voice accuses the
staff members of murder as well, and Thomas has to go check on Ethel because she's having a panic
attack that makes her pass out. While Thomas takes Ethel to her room so Edward can check on her,
Anthony freaks out and grabs William to demand answers since supposedly he was close friends with
the Owens. William has not choice but to confess he's a detective and not a businessman. Edward
prepares a mild medicine to help Ethel sleep and after he leaves, Ethel freaks out about having
been discovered, but Thomas tells her to keep quiet. A moment later, everyone gets together
to discuss what happened and Thomas explains the Owens left him instructions to play the record
after dinner, but he had no idea of its contents. Thomas wouldn't have played it if he had known
and explains that he and his wife didn't kill anyone, but in a flashback, it's shown he did use
a pillow to kill their previous employer while Ethel watched. Anthony and Emily deny knowing
what the recording was talking about, and Edward explains the name mentioned by the recording was
a surgical patient whose procedure got the usual complications and didn't survive. John says his
supposed victim was just a soldier that died in the war, and Lawrence explains he gave the
death penalty to a criminal that everyone thought innocent but he had access to extra evidence as a
judge. William's man drowned in his own puke while in jail, and Vera worked as a governess
for a little kid that sneaked off and drowned in the sea when he wasn't supposed to swim. All these
were clearly accidents, but Philip doesn't deny his own case and admits he did kill twenty-one
men in Africa. Everyone else calls him a monster, but Philip points out he was on a job and wasn't
any different from regular soldiers. This prompts Anthony to suddenly remember the names, they were
two kids that were playing in the dark and he accidentally ran over them with his car. However
in his memory, it's clear that it was daytime and he was just driving like a maniac. After telling
his story, Anthony takes another sip of his drink and suddenly begins choking. The other guests
carefully lower him on the floor but when Edward checks on him, he confirms Anthony's already
dead. The men take the body to Anthony's room and find the illegal uppers, but William forbids them
from hiding them because this is now a police investigation. Afterward, everyone agrees to go
to bed and leave in the morning. Ethel continues to have nightmares about the night of the crime,
but her dreaming is interrupted by a mysterious knock on the door. Edward also spends the night
having nightmares about the operation that went wrong filled with blood and guilt. He's
suddenly woken up in the morning by Thomas, who wants him to check on his wife. Unfortunately by
the time Edward gets there, he can only confirm Ethel has been dead for a few hours. Meanwhile
Philip decides he'll go to breakfast with his gun just in case. When he leaves his room, he
finds William looking at Anthony's body and making an important discovery: Anthony's mouth smells of
cyanide. Edward bumps into Vera, who brings him to the dining room to show him that now there
are only eight figurines on the table. Edward doesn't take her seriously, and after he leaves,
Vera has a vision of her old employer Olivia that reminds her of the day she lost the kid. She,
Olivia, and the child Cyril were having a nice day on the beach, and Olivia had to scold Cyril for
wanting to swim when he wasn't strong enough to do it. Later they were joined by Cyril's uncle Hugo,
who Vera instantly fell in love with. A moment later, everyone has breakfast prepared by Thomas,
and Vera insists on asking about the figurines, but the others swear they didn't touch them. Vera
is still worried because Anthony's and Ethel's deaths match the lines of the poem, and she thinks
healthy young men like Anthony don't die out of nowhere. She wonders why Edward brought medicines
with him if he came for a party and not for work, prompting Edward to admit he was supposed to treat
Mrs. Owen. Vera still thinks they should check his bag and Edward finally gives in but only
after pointing out that then they should also check Lawrence's things because Edward saw him
in the cancer ward in his clinic. Both suitcases are checked but they only find mild medicine,
nothing dangerous, and an offended Edward throws Vera's suitcase open in revenge. Afterward,
Philip approaches Vera in private and explains he killed those men for diamonds before asking
Vera about her own truth, but Vera sticks to her story. She loved the kid and almost drowned too
trying to save him. Meanwhile John's packing his things and remembering the day his friend Henry
died. During the war, John found letters from his wife in Henry's jacket because they had been
having an affair behind John's back. When he saw Henry again, John pretended everything was fine,
but as soon as Henry turned around, John shot him. Downstairs, Philip's asking Thomas for more
information, and Thomas explains he and his wife had been on the island for a week but they never
saw anyone except for the sailor that came with supplies. Philip thinks the Owens must be hiding
somewhere on the island and William agrees to go searching with him. While they look around
together, William tells Philip about how his prisoner fell in his cell, but it's revealed that
William had actually beaten the poor guy to death. John is also out for some fresh air, and when Vera
checks on him, he confesses his wife died of influenza after the war and that he regrets not
letting her be happy. He also thinks the boat won't come and that they're stuck here. After
Vera leaves, John has a vision of Henry haunting him. In the house, a drunk Edward joins Philip and
William on their search. They hear a noise coming from Anthony's room and Philip rushes in with his
gun out, but it's only Thomas, who was looking for a camp bed that was stored in that room because he
doesn't want to sleep next to his wife's body. Unlike the guests, he isn't allowed to leave
when the boat comes. In the meantime, Vera helps Emily with her wool and gets to hear her story,
which she hadn't wanted to share in front of the men. Emily had hired a foundling girl as her maid
and taught her all she knew. But the girl got into trouble and Emily refused to help her,
so the girl ended things for herself. After Vera goes inside for some tea, Emily notices there's a
storm coming, but the birds are actually strange. When she comes closer to check, she discovers the
birds are flying above John, who is now dead. A moment later, the men bring John's body inside,
and William confirms this is without a doubt murder. Vera checks the figurines again and
notices another one went missing. Remembering how she failed to save Cyril and scared by all these
deaths, Vera goes to the beach to end things, but Lawrence stops her and brings her back into the
house. The guests have a meeting to discuss things and start by asking Philip about his
gun. He explains he wasn't invited here, he had also been hired by Isaac under Owen's orders,
who paid him well for coming as a mercenary ready to act if necessary. Lawrence came because he was
told a friend of his was going to be here, Emily came because Mrs. Owen had been interested in
her work on education, William was told someone would come under false pretenses and a cop would
be needed so Owen supplied a list of guests, and Edward came as a doctor for Mrs. Owen. However,
everyone got these invites through letters and never got to meet the Owens. At that moment,
Lawrence realizes that the initials that signed the letters were U. N. Owen, which
sounds like "unknown". Lawrence thinks this is a riddle and the killer is one of them. Meanwhile
Thomas discovers there are some liver and kidneys missing from the fridge. The boat never comes,
so when night falls, everyone goes to sleep and locks their doors. Emily prays for protection
and gets terrified when she has a vision of her maid appearing next to her. The next morning,
Edward desperately hits the gong downstairs to make everyone wake up because he found Thomas
dead. The killer had used an ax, once again matching the poem and proving Vera right. While
Philip and William take the body to his room, Vera makes coffee, but Emily doesn't drink it because
she can't trust it. Edward approaches Lawrence in private and after apologizing for telling
everyone about his illness, he asks him for an alliance, which Lawrence accepts. Sometime later,
Vera's walking through the house when she sees something that shocks her and makes her check on
the figurines, confirming another one's missing. She then hits the gong to call for everyone and
show them Emily's also dead. The killer used a knitting needle to imitate the bee sting from
the poem. After taking Emily's body to her bed, Philip returns to his room, only to discover his
gun's gone. He calls for a meeting and points out he had locked his room, which means someone must
have a master key. An argument begins as they start accusing each other of being the killer,
and the tension only goes away when William offers as an alibi that he had been constipated in the
bathroom. Afterward, they search every room for the gun, and they even undress to only wear a
towel or a robe in order to avoid hiding anything in their clothes. Vera changes into the swimming
suit she had been wearing the day Cyril died, which makes her remember how Cyril had wanted
her to marry Hugo and be his aunt. When she looks at herself in the mirror, Vera finally notices
that there's a strange hook on her ceiling. Later, when Vera sees Philip in just a towel,
she decides to undo her robe as a silent method of flirting, and they agree to start calling each
other by their first names, unaware that Edward's watching them. All the bedrooms are clear, so the
group begins searching the rest of the house, but they don't find anything. For dinner, they
eat directly from the cans to make sure nothing is poisoned while the camera reveals the gun and
the key are hidden inside a bear rug. Later while they drink, Vera keeps thinking about Cyril and
a conversation she had with his mother. Olivia explained she hadn't known she was pregnant when
her husband died so Hugo stepped in to inherit everything, but when Cyril came along all his
dreams of fortune were shattered. Vera decides she wants to make some tea and everyone goes with her
to the kitchen for safety. The men take the chance to ask Lawrence about all the death penalties he's
given, and Lawrence admits he went to see every criminal die because it was his responsibility.
The recording had accused him of killing Seton, who the news thought was innocent, but Lawrence
had been given Seton's diaries where he wrote all the dirty things he did. Seton had been different
because he refused the hood in order to look Lawrence in the eye while he died, and that look
still haunts Lawrence. Hearing the word haunt makes Vera see Cyril standing nearby, but also
makes her remember getting frisky with Hugo on the beach. Afterward, Lawrence goes to the living room
to read and Vera returns to her bedroom. While she's washing her face, Cyril appears behind her,
and suddenly a hand appears on the sink and tries to kill her. As memories of Cyril's death flood
her mind, Philip and Edward come to the room to find her on the floor, explaining she had had a
panic attack. She turns down the brandy that William brings her because she's suspicious,
so Philip goes looking for a closed bottle. The group begins to drink and discuss the weird
hook in Vera's bedroom, but they suddenly realize Lawrence didn't come when Vera screamed. They rush
downstairs and discover Lawrence has been shot in his reading chair, just like the poem says.
The body is taken to the corresponding bedroom and while everyone argues over accusations,
Vera finds another figurine gone. The group hates the fact they can wait to die, so they decide to
throw a party where they get drunk and consume Anthony's illegal uppers while listening to the
recording with the accusations. Philip and Vera get very close while dancing and Edward tells
William about his suspicions of the young couple working together. Philip promises Vera that he'll
protect her, and when it's time for everyone to go to bed, Philip follows Vera to her room so
they can spend the night getting busy. Meanwhile William thinks about the night his prisoner died.
The poor boy had been accused of watching other men inappropriately in a public bathroom and
William tries to imagine himself letting the guy go, but even in his imagination he ends up killing
the guy. At that moment, William hears a noise and leaves the room to discover Edward running
downstairs, so he goes to pick Philip up to go after him together. Vera's left alone in the room
and begins thinking about the past again. While she was in the hospital after she almost drowned
trying to save Cyril, she was visited by Hugo, who acted very cold toward her. He informed her
she was fired because there wasn't a kid for her to watch anymore, but he left her some money and
refused to see her again. Sometime later, Philip and William return without having found Edward,
but Philip does find his gun just lying on his bed and another figurine goes missing. Vera remembers
that the next death is by a red herring and thinks Edward's still alive, especially since the party
had been his idea. William begins wondering if they're all already dead and this is hell, finally
admitting he did kill his prisoner, and Philip has to calm him down. Afterward, William begins
looking for Edward, only to suddenly see a huge bear coming after him. Philip and Vera go to the
cliff with the intention to start a big fire that could get a boat's attention, but they realize
William didn't come with them. They return to the house and find William dead under the bear rug,
matching the zoo bear from the poem. Now there are only two figurines left on the table. Then Philip
and Vera return to the cliff, noticing something on the rocks now that the tide has lowered. It
turns out to be Edward, who is also dead. Vera asks Philip to move the body, but as soon as he
turns around, Vera steals the gun from his pocket, thinking he's the killer. Philip tries to take the
gun from her and in the struggle, his shoulder's shot. Vera then shoots all the remaining bullets
until he's dead. As Vera goes through a breakdown, she remembers the day she testified in court about
Cyril's death being an accident. She explained that she ran as fast as she can to save Cyril
yet didn't make it in time, and everyone believed her except Hugo. When they talked in private, Hugo
pointed out he saw her run while playing games and she was very fast, thus he believed she slowed
herself down to let Cyril die. Vera denied it, but in her memory, it's revealed Cyril didn't sneak
off. Vera told him to go swimming and she did slow down on purpose so Hugo could inherit the money.
At that moment, Vera sees Cyril again, who takes her back to the house to show her the hook in her
bedroom now has a rope. Vera gets in the chair and decides to end things like in the poem, only
to change her mind when she sees the door open and Lawrence comes in. In her shock, she accidentally
kicks the chair, so she tries her best to stay up while barely breathing and hearing what Lawrence
has to say. It turns out the Owens don't exist, and everything had been a plan by Lawrence to get
justice for all the people the guests killed. He had faked his own death using the liver and
kidneys he stole from the fridge, and everyone believed the doctor when he confirmed it, but
Edward had lied for the sake of their alliance. Lawrence explains Seton's diaries weren't made
public because they were too disturbing, but they woke something in Lawrence, and when Seton looked
at him when he died Lawrence finally understood they were the same. Lawrence's tumor never got
better and he's planning to use the gun to match his own death with the poem, that way
the police will find ten bodies but no murderer because they'll be chasing after the nonexistent
Owens. Vera tells him there aren't any bullets left for him, so they should lie together and
tell the police Philip killed them all. However Lawrence moves the chair and finally kills Vera
as he reveals he still has the bullet he took from the gun to fake his own death. Afterward, Lawrence
goes to the dining room and puts the ten figurines together again. He prepares the chairs and drinks
to make it look like he had company, then uses the gun to finish the plan exactly like the poem.