The movie begins in October 1944, four years into World War II.
On a downcast afternoon, Nazi soldiers raid a village to round up all the Jewish people
with Saul Ausländer, who works as a Sonderkommando Jewish–Hungarian prisoner in Auschwitz.
As the massive wave of people is forced into the streets, he and other workers quietly
escort them to the concentration camp's holding area.
Once there, the Jews are instructed to strip off their clothes and leave their valuables.
Officers lead them inside a gas chamber and perform a mass genocide.
While this process is underway, Saul and the workers wait patiently outside.
With everyone dead after inhaling the poison inside the chamber, they drag the corpses
out and clean the whole area before another group arrives.
The stoic Saul busies himself scrubbing the floors when the workers become stunned to
discover a young Jewish boy still barely breathing despite inhaling the toxic gas.
He is immediately brought to a room where a Nazi doctor checks his vitals.
Saul peeks inside the room as the doctor calls for an autopsy of the boy.
Feeling somewhat conscious-stricken, he takes it upon himself to carry the boy's body to
the operating room where the designated prison doctor, Miklós Nyiszli, is stationed.
Despite knowing his servitude to the SS Angel of Death, Josef Mengele, he pleads with him
to help, letting him know he is a fellow Hungarian.
He asks the doctor to leave the boy's body untouched to be properly buried, but Miklós
declines since he will just be burnt like the other corpses.
However, the doctor allows Saul to spend five minutes alone with the boy in the evening
before the cremation.
Afterward, he returns to his duties with the cleanup crew.
However, he is castigated for asking too many questions about the convoy of Jews.
Later before the workers collect all of the valuables left behind by the Jews, Saul thinks
about looking for a Rabbi to perform a Jewish funeral for the boy.
With the help of a fellow inmate, he is pointed to the crematorium, where Rabbi Frankel prepares
the live coal.
Though he explains the situation, the Rabbi implies he is powerless to do anything and
can only pray for the boy on his lonesome.
Later, he joins Sonderkommando Abraham, tasked by the Oberkapo Biederman to collect gold
and recover documentation in preparation for an uprising.
He asks Abraham to help find another Jewish minister, so he gets informed about the Greek
Rabbi 'The Renegade' in another command unit led by another Oberkapo, Mietek.
The inmates describe him as a scarred man who lost his faith.
Later in between shifts, Saul sees the Oberkapo requesting Abraham to smuggle photographs
outside the camp, which will serve as evidence of the concentration camps inhumane atrocities
towards Jewish people.
Since the office of the Nazi commander is locked, Saul volunteers to be the locksmith
of the operation, despite only being skilled at watch repair.
He believes in finding The Renegade by offering his assistance to their scheme.
Sometime after, at the courtyard, he is instructed to go with fellow inmate Katz to perform a
repair job, receiving a piece of jewelry as a bribe in case he gets compromised.
They arrive at a shack with Saul pretending to fix the front door lock while the Oberkapo
deals with Mietek, who is keeping watch of the prisoners.
Simultaneously, Katz steals a camera inside the shack and immediately photographs the
outside cremation.
Fearing for their safety upon hearing guards approach, Saul hides the camera by a nearby
drain.
While they are ordered to continue the locksmithing job, the officers search the shack but find
something that needs to be seen.
Saul then continues his quest to locate the Greek Rabbi by sneaking onto a transport truck
to join another Sonderkommando unit.
He and the prisoners reach a nearby riverbank, where the ashes are thrown into the river.
Upon arriving, he sees The Renegade busy shoveling on the shoreline.
He demands help to pray for the young boy at his funeral, but he gets ignored.
To coerce him, Saul recites a Jewish blessing to alert Mietek.
When that does not convince him, he throws his shovel into the river, forcing The Renegade
to retrieve it.
Seeing that he does not care about drowning, Saul, who does not know how to swim, barely
pulls him out, alerting the SS guards in the area.
Though unable to speak Hungarian, the commandant interrogates Saul through a translator.
Satisfied by the reasoning, he allows him to return to work but has The Renegade killed
as punishment.
Mietek, who realizes that Saul is from another unit, confronts him.
Still, fortunately, he is appeased when given the jewelry hidden underneath Saul's sock.
Returning to camp in the evening, following a roll call, Saul quietly sneaks into the
doctor's office, not knowing he would intrude Nazi officers who come to inspect the area.
Caught red-headed, Saul reasons he is cleaning the room, but one of the officers teases him,
playfully dancing a Jewish dance to mock his heritage.
After getting forced out of the room, he returns to the crematorium defeated and looks after
the corpses, failing to find the boy's body.
During the workers' downtime, a forlorn Saul angrily confronts Miklós, who guarantees
the child is hidden from the other doctors.
The doctor escorts him outside the autopsy room, but instead of waiting for him to finish
work, Saul enters and carefully sneaks out of the child's body, wrapping him inside a
large brown sack to avoid detection.
After walking through the hallways filled with workers, he climbs upstairs to the barracks,
almost getting castigated by one of the inmates if not for his threat to expose his secrets.
He then places the boy on a cot in his room.
He goes to the basin to wash his hands when Abraham informs his weapons have been smuggled
into the camp, so they must prepare to execute the uprising by morning.
Saul insists on still needing a rabbi to pray for the boy, with Abraham assures he can pull
through with someone if they succeed in escaping.
Not long after, while having dinner, Saul is called to a brief meeting by the inmates,
asking him to learn about handling a firearm.
Suddenly, the trucks filled with new groups of Jewish captives are brought to the camp,
prompting the workers to resume their duties.
Biederman escorts Saul outside the courtyard to meet with SS-commandant Moll, who orders
the Sonderkommando to clean the dining table in the board room.
He later witnesses a conversation between Biederman and the commandant, who orders the
Oberkapo to list down seventy names in his unit.
Though the purpose of the write-up is unclear, Biederman suspects the list of people will
be executed soon.
Saul then returns to the crematorium to summon another inmate per the commandant's instructions.
He is immediately put to another work detail by shoveling coal into the burning furnace.
Afterward, he gathers with the group outside, where Biederman reveals the list to Abraham.
He then instructs a hesitant Saul to escort a few inmates to the women's camp, where they
must acquire a package of gunpowder from a prisoner named Ella, who Saul knows personally.
They soon transport piles of valuables to the other camp, and by bribing a guard, they
are led to the parking area, where the caretaker summons Ella.
Upon seeing Saul, she freezes momentarily and gives him a small bag of gunpowder.
She gently clasps his hand, hinting at past feelings, but he resists, leaving the area
hurriedly while she calls him out by his first name.
After the successful acquisition, several new batches of Hungarian Jews gathered outside
the lot and get escorted to a woodland area called 'The Pits' since the furnace chambers
could no longer occupy everyone.
While no one notices, Saul deliberately bursts into the terrified crowd, looking for a rabbi
among them.
As they get closer to the woods, gunshots are heard, revealing that the officers are
executing the Jews as they arrive.
Not long after searching around, a Frenchman named Braun approaches, convincing Saul that
he is a rabbi.
As the scene turns chaotic, with everyone asked to strip naked to be either burned alive
or shot into a pit, he tries to sneak the Rabbi into the camp but gets caught in the
frenzy.
Luckily, Miekel recognizes Saul, saving him from getting killed by the Jews, though he
asks for two bracelets as payment.
When the Oberkapo leaves, Saul reunites with the Rabbi and then disguises him as a member
of the Sonderkommando.
He asks his help to perform a Jewish burial for the boy, who he reveals is his son.
They return to camp and gather with the men listed by Biederman, who perished during the
chaos at the pits.
Through some reasoning, the SS commandant allows the men to enter the grounds despite
making only 67 men.
As they reach the cells, Rabbi Frankel, who denied his request, reprimands him for smuggling
an outsider, but Saul insists the child must be prayed over.
While Braun sits, he unfurls the cloth and cleans his son's body with water.
Suddenly, Abraham appears, confronting him about the package, only to find out he lost
it while shuffled around by the crowd in The Pits.
One of the plan organizers discovers his failure and punches him in the stomach.
Abraham then questions him about the dead boy, insisting he is not his illegitimate
son.
He tells him to keep the Rabbi hidden and dispose of the corpse before leaving the room.
Later, Saul cuts Braun's beard to make it shorter.
The following morning, he and the Rabbi hastily dig a grave for his son, only to be summoned
inside with the inmates when an alarm blares.
While waiting in a holding area, the prisoners call Saul out for disregarding everyone's
safety by including Braun in their fold.
He reasons with Abraham, who continually denies he ever had a child.
Later, the SS officers line up the prisoners in the courtyard for roll call and get physically
examined by Miklós, who secretly tells Saul he will need a replacement corpse like the
one he took.
The inmates are then ordered to return to the crematorium to resume their tasks when
they discover that Biederman's unit has been killed by the SS.
Abraham causes a scene that leads to an all-out riot with the other prisoners who attack the
SS guards.
As Saul protects the Rabbi from the scuffle, he is found by the Kapo organizer, instructing
him to fight back despite his hesitation.
The men climb upstairs and head outside the courtyard, where the rebellion continues.
Saul hurriedly returns to the dig site and retrieves the boy's corpse, constantly dodging
gunfire and bombs to reach the outer area.
He then escapes unscathed to the woods with Braun and other inmates running in different
directions.
They flee far away as possible until they cannot hear the sound of sirens in the camp.
Not long after, the pair of escapees reach the riverbank.
As Saul lays his son's body on the ground, he digs a grave hurriedly, ordering Braun
to recite the Kaddish, a Jewish mourning prayer.
Unfortunately, the prisoner claiming to be a Rabbi reveals himself as a fraud when he
fumbles over the words of the prayer.
Suddenly, more escaped inmates arrive and swim to freedom, with Braun joining them.
With the SS guards slowly reaching the area, Saul carries the boy's body across the river.
However, the current is too fast, making him struggle to stay afloat because of the added
weight.
He then loses grasp of the corpse but is safely pulled out of the water by Rabbi Frankel.
Saul becomes forlorn, losing the boy as it drifts afloat away from him.
The Rabbi gets him on his feet and guides him as the inmates travel on foot, arriving
at a shed in the forest.
While recuperating, they discuss joining the Polish resistance now that the Red Army is
reported nearby.
Curiously, Saul notices a young peasant boy peeking outside.
He then smiles at him, seemingly reminded of the son he lost.
The movie ends as the boy runs away before an SS officer grabs and keeps him quiet as
guards rush toward the shed.
After he is released, the boy races into the thick forest as gunfire erupts from the opposite
direction, implying the inmates have been discovered.