In the year 2063, human's bad treatment of the planet has raised the sea levels to the
point where most of Earth is flooded now. Only two continents remain, and currently
they're fighting a war over land and resources. In the middle of the sea between both continents,
there's a military outpost known as The Sentinel with a crew of four soldiers that are starting
to grow frustrated. After two years of service, their contract ended three months ago, yet the
relief crew hasn't come to pick them up yet. Food is getting scarce, so during a very stormy night,
Cassidy and Sullivan decide to try fishing. Surprisingly they do well and fill their big net
with plenty of catches. Meanwhile their superior officer Hendrichs notices the storm is getting too
violent, so he asks Baines to secure the giant explosive that guards the Sentinel. At that
moment, the waves begin growing big and violent, affecting the outpost's pipelines. Baines rushes
to fix them and gets his hand stuck, causing him to struggle underwater for several minutes until
he finally can free himself. Outside, the waves take the net away and the duo loses their bounty.
Sullivan tries to grab something again, but the wind is getting too strong and dangerous, so he
has to rush back inside before he's taken away too. Everyone makes it back just in time before
the enormous wave hits the structure, causing it to shake and pushing water through every entrance,
but the Sentinel is still standing when it's over. The next morning, the group discuss how to lower
the consumption of their resources while having military rations for breakfast. Baines wonders
what happened to the fish and gets angry when he hears they lost them, and Sullivan retaliates by
insulting Baines for taking parts from his kitchen to repair the main pipes. An argument ensues and
Henrichs reminds them to behave like adults, asking them to concentrate on the repairs.
Baines wonders why they don't ask for the relief to hurry, but Hendrichs reminds him the telegraph
is to make reports only. Afterward, Sullivan does the daily report using the telegraph. He
informs the base that there have been no events, and they reply there are no events there either,
same as the last few months. Sometime later, Sullivan joins Hendrichs outside and after
making some jokes about their air dancer, Sullivan looks at the sea with the binoculars. He's shocked
to discover a ship is approaching, which Cassidy confirms when she checks the radar. Sullivan gets
very happy because he assumes it's the relief, but Hendrichs is wary and orders Baines to bring
some weapons in case it's the enemy. Cassidy tries to contact the ship yet gets no answer,
so Henrichs decides to give the ship a chance. He hands Sullivan a gun and tells him to take
the boat to meet the ship and make sure there aren't any enemies to worry about.
Sullivan immediately takes off and approaches the ship, calling out for any possible passengers,
but there's still no answer. With his gun out and ready, Sullivan boards the ship and begins
investigating, getting more and more upset when he notices the clues. Objects are covered with dirt,
the radio isn't working, and there's untouched food in the cabinets. Hendrichs tries to contact
him for a status update, but Sullivan ignores him as he finds four bags destined for them. This had
been their relief, but something happened to the crew and they disappeared, meaning they missed
the chance to go home. Because Sullivan isn't responding, Hendrichs assumes he was attacked,
so he wants to shoot the ship before it approaches the Sentinel. He asks Cassidy for one of the keys
to the explosive, and when she hesitates, he reminds her this is protocol. Together with his
own key, Hendrichs starts activating the explosive and before he shoots, he tries contacting Sullivan
one last time. Thankfully Sullivan does answer this time and the attack is canceled. However
when Cassidy asks for her key back, Hendrichs informs her he's keeping both as punishment
for her hesitation in following orders. Afterward, Sullivan tows the ship over to the Sentinel. While
Hendrichs proceeds to investigate the ship, Sullivan reunites with Cassidy and they spend
a few moments getting frisky to make up for the scare they just went through. A few hours
later while they have a quick iodine bath, Baines informs the team of all the things he's managed
to salvage from the ship. He's also sure this was the relief and that the engine hasn't worked in
months. Sullivan wants to send a message to the base but Hendrichs forbids it until they get more
information, since nothing about this makes sense even if it does count as an "event". The crew
is starting to get tired and wary of Hendrichs' attitude, especially when they notice he has both
keys now. After the shower, Hendrichs checks the ship's navigation history and writes down all the
coordinates, which he takes back to the Sentinel to apply them on a map to follow their trip.
Meanwhile Cassidy and Sullivan talk about what the world must be like out there, since they haven't
seen it in two years. Sullivan admits he sent a message behind Hendrichs' back, so they'll have
an answer tomorrow. The next morning, Hendrichs finds his three soldiers suspiciously waiting next
to the telegraph and Baines confesses the truth. Hendrichs intends to scold them for it, but at
that moment the machine receives an answer. The group gets excited until they read what it says:
it's exactly the same message Sullivan sent last night. It's then that they finally realize they
lost contact with the base a long time ago, and the computer has just been sending back the "no
events" message Sullivan sends every day. While Hendrichs continues to work with the coordinates
on the map, Baines begins sneaking into the ship with a plan in mind. One night, Sullivan catches
him coming back, but Baines refuses to explain himself. The duo ends up drinking together,
and Baines shares some stories about the family that awaits him at home, if home is still around
at all. Suddenly, Baines confesses he thinks he can fix the ship. Excited by the hope of escaping,
Sullivan rushes to give Cassidy the news and asks her to leave with him to live together
in one of the few safe towns that are left on the continent, but Cassidy's hesitant and won't
believe what she's hearing. The next day, Sullivan sneaks into the ship with Baines to help him fix
the engine and together they manage to finish the job. As soon as they come out, they find
Hendrichs waiting for them, and he orders them to take down the ship to use its parts to fix the
Sentinel. He won't allow them to leave because he claims that staying here is their duty, regardless
if their contract has ended. Sullivan refuses to die here like it happened to others in the past,
and Baines agrees, but when Cassidy joins them, she doesn't show support for them. Not caring
about their arguments, Hendrichs sends the team to work on repairs, threatening them with his gun if
they don't obey. The guys are furious and afraid Hendrichs has been too trigger-happy lately,
so Cassidy volunteers to talk to him next. Cassidy tells Hendrichs she understands he feels after he
lost his last squad, but going away doesn't equal dying, if anything it's salvation. Meanwhile
Sullivan and Baines are starting to wonder if they'll have to fight their boss to get what
they want. Their conversation is interrupted by Hendrichs, who admits Cassidy has presented a good
argument: since they don't have communications, someone should report to the base. Two people
get to stay, and two others should go. Hendrichs is obviously staying, and Cassidy has volunteered
to stay here as well. Baines is happy with this development, but Sullivan is heartbroken. Moments
later, Sullivan talks to Cassidy in private, trying to convince her to come as well, either
by replacing Baines or disobeying Hendrichs. He's so desperate to make her happy that he even offers
to take her place or stay here with her, but Cassidy snaps and tells him she doesn't love him,
she's only thought of him as a human necessity. A devastated Sullivan rushes out of the room,
and Cassidy breaks down in tears. That night, Sullivan and Baines concentrate on packing.
Hendrichs gives Sullivan a letter to take to the base, and he comments on the fact that the enemy
is exactly like them: soldiers that just want to protect their homes. Sullivan reminds Hendrichs
they could all leave together, but Hendrichs still refuses, saying someone needs to keep
an eye on the explosive. Afterward, Hendrichs goes to finish his work on the map and the coordinates,
making a shocking discovery: the relief ship has steered away from the Sentinel on purpose,
which makes no sense. Getting suspicious, Henrichs rushes to check on Cassidy, but he doesn't dare to
say a word. The next morning, the team wakes up hearing the alarm blearing because another
ship has appeared on the radar. The men rush to get on their positions to defend the Sentinel,
and Cassidy tries to get in contact with the ship to no avail. This time Hendrichs refuses to send
anyone and orders the team to shoot, but their first bullet misses. While they're getting ready
to reload, Cassidy notices their ship is missing at the same time Sullivan and Baines finally get
to see it clearly once the fog clears out. They refuse to shoot again, but by the time Cassidy
comes to warn them, it's too late: Hendrichs has his gun out and hits Baines with it. It was
Hendrichs that put the ship back out last night, and to prove he's being serious, he shoots the
air dancer. Baines still refuses to destroy the ship and Hendrichs responds by shooting his ear,
so Sullivan takes the cannon and destroys the ship before they lose a life. A furious Baines
tries to go after Hendrichs, but Cassidy knocks him out first with a fire extinguisher. Afterward,
Sullivan and Cassidy lock Hendrichs up in the pantry and Cassidy takes back both keys. A furious
Baines later tries to find Handrichs to kill him and ends up hitting Sullivan when he tries to
stop him. Cassidy calms him down with words, but Baines still leaves to get drunk alone and unpack
his things, which makes him cry. Sometime later, Cassidy mentions Hendrichs needs his iodine bath,
but Baines refuses to let him out and announces he quits. Sullivan tells Cassidy that they have
no choice but to go through every single channel on the telegraph until they find one is working,
and Cassidy takes the chance to confess she hadn't meant what she said about him. She had only wanted
him to leave without having to worry about her, but Sullivan is hesitant to accept the excuse.
Later in the afternoon, Sullivan takes some food to Hendrichs and wonders why he changed his mind
about leaving. Hendrichs shares the information he got from the coordinates: the relief ship was
here three months ago like it was supposed to, but something made it move away. This means there's
a traitor among them that wants the explosive. Sullivan doesn't believe him and leaves, locking
the door again. While Sullivan spends the rest of his day sending SOS messages to every channel,
Baines keeps on drinking and tries to keep himself busy in his workshop, but he soon loses his mind
and destroys everything he's built. Later in the evening, Cassidy shares with Sullivan a picture of
her as a kid with her family, explaining they were killed by the enemy when she was still a child.
The next morning, Baines finds Cassidy sleeping in the comms room. As he spouts nonsense about a
missing future, he attacks Cassidy, making it seem as if he wants to take advantage of her.
After some struggle, Cassidy manages to push him away, not realizing Baines has stolen the keys.
Then Cassidy goes looking for Sullivan to tell him what happened, but at that moment Baines' voice
can be heard through the speakers announcing that he'll activate the explosive. Sullivan and Cassidy
rush back to the comms room and try to calm him down, mentioning his family as a reason to keep
living. Baines cries as he steps away from the controls, but after Cassidy takes back the keys,
Baines admits he just forgot the last digit of the activation code. Sullivan thinks it's time to let
Hendrichs out, but Baines has shocking news: he tried to kill him earlier, but when he entered
the pantry, Hendrichs was gone. An open window indicated he had ended things for himself. When
Cassidy and Sullivan check the pantry, they're devastated to see Baines said the truth. Not
being able to deal with his grief, Sullivan reads the letter Hendirchs had written to the base,
and he's shocked to see Hendrichs had requested for his command to be extended. Afterward Cassidy
shows the now clean workshop to Sullivan to prove Baines is feeling better and is building again.
Baines confesses his wife had been pregnant and he never got to meet the baby, which causes Sullivan
to easily forgive him for the drunk outburst. Baines shows his gratitude with a hug before
getting on the boat to go back to salvaging stuff from the sea. Cassidy is going with him,
so Sullivan gives her a gun just in case, and Cassidy thanks him with a kiss. Moments later,
Sullivan decides to try fishing again, and when he pulls up the net he discovers Hendrichs' body
with a wound on his head, meaning someone killed him and there truly is a traitor with them. While
Sullivan runs to check on his friends' profiles for clues, Cassidy stares at Baines in the boat,
putting together a plan. Next, Sullivan checks on Hendrichs' map, coming up with a theory. As a
storm begins brewing, Sullivan checks the beacon outside and confirms it can be taken off and
moved around. This means someone took the beacon away in the boat and made the ship follow them
instead of going to the Sentinel, explaining the coordinates. Then that someone killed the relief
team and let the ship float away. A few hours later, only Cassidy comes back from the little
trip saying that Baines accidentally fell and died while trying to grab some plastic. Sullivan
immediately guesses she killed him and she was the traitor all along, however he's too scared to say
anything yet. The next morning, Cassidy wakes up alone in bed. Sullivan talks to her only through
the walkie-talkie, explaining he knows she killed everyone and that she's spying for the enemy,
but he won't let her have the explosive. Cassidy then realizes she's missing the keys and runs to
the comms room, where she finds Sullivan in the middle of activating the explosive. Since
they have no future, he doesn't mind blowing the Sentinel up with them still inside. With
Sullivan holding her at gunpoint, Cassidy tries to explain people in her homeland are suffering
and she hated lying to him, but Sullivan doesn't believe her and activates the explosive. However
instead of exploding, the machine displays a funny little phrase that Baines liked to repeat,
which makes them realize Baines reprogrammed the explosive so nobody can use it for destruction.
In the end, Sullivan and Cassidy have a little talk. They agree that no matter
what side of the war comes, they'll protect the Sentinel together and keep on surviving.