In a New York City nursing home, the elderly and incapacitated Auschwitz concentration camp survivor Max Rosenbaum has befriended the dementia patient Zev Guttman, whom he recognized from their days at the camp. Max has continually reminded Zev that their families were murdered at the camp by the Blockführer Otto Wallisch, who emigrated to North America under the false name Rudy Kurlander. Max convinces Zev to avenge their families by seeking out and killing Wallisch. Max directs Zev to a gun shop, where he buys a Glock, and then to four men in the U.S. and Canada named Rudy Kurlander, one of whom is the former Blockführer.
Zev confronts the first Rudy Kurlander, a German veteran of World War II, in his home, but this Kurlander proves that he served in the North African Campaign under Erwin Rommel, and was never near Auschwitz. Zev finds the second Rudy Kurlander in a nursing home in Canada, but he turns out to have been a prisoner in Auschwitz, sent there as a homosexual.
Zev arrives at the house of the third Rudy Kurlander. His son John, a state trooper, tells Zev that his father died three months ago. John reveals, after several glasses of whiskey, that his father was only a boy and a cook during the war. When John, who is a neo-Nazi, realizes that Zev is Jewish, he becomes enraged and lets loose his German shepherd. Zev shoots the dog and then John, collapses in exhaustion on John's bed and leaves the house in the morning.
Zev arrives at the home of the fourth Rudy Kurlander and his family, and recognizes him from his voice as the Auschwitz Blockführer. Zev threatens to shoot Rudy's granddaughter unless he confesses "the truth". Rudy admits to his daughter and granddaughter that he was in the SS, and killed "many" people. However, he says his real name is Kunibert Sturm — and Zev himself is Otto Wallisch. They were both Blockführers, and after the war, tattooed each other to pose as Jewish survivors. Shocked, Zev shoots Sturm and then, declaring "I remember," fatally shoots himself.
Back in New York, the horrified nursing home residents watch television news reports of the murder/suicide. Max reveals that he recognized Zev as Wallisch when he arrived at the nursing home, and that Wallisch and Sturm killed his family.