The Oxford Murders
Tags: romantic, mystery, philosophical, murder, flashback

Plot synopsis:
In 1993, Martin (Elijah Wood), a US student at the University of Oxford, wants Arthur Seldom (John Hurt) as his thesis supervisor. He idolises Seldom and has learned all about him. He takes accommodation in Oxford at the house of Mrs. Eagleton (Anna Massey), an old friend of Seldom. Also in the house is her daughter, Beth (Julie Cox), who is her full-time caregiver — which she resents bitterly — and a musician by occupation.
In a public lecture, Seldom quotes Wittgenstein's Tractatus to deny the possibility of absolute truth. Hoping to impress his idol, Martin disputes this, asserting his faith in the absolute truth of mathematics: "I believe in the number pi". Seldom humiliates him, ridiculing his arguments and making him look foolish in front of the audience. Disillusioned, Martin decides to abandon his studies and goes to his office to collect his belongings. There, he encounters his office-mate, a bitter mathematician Podorov (Burn Gorman), who also failed to become a student of Seldom's.
Martin then returns to his residence, where he finds Seldom arriving to visit Mrs. Eagleton. The two men enter the house together and find Martin's landlady murdered. Seldom tells the police that he had received a note with his friend's address marked as "the first of a series". As Seldom is an authority on logical series, he argues that a serial killer is using murder as a way to challenge his intelligence. According to Seldom, "The only perfect crime that exists is not the one that remains unsolved, but the one which is solved with the wrong culprit."
Martin and Seldom discuss how easily the murder of the old lady might have been overlooked, particularly as she already suffered from terminal cancer. Martin suggests that the murderer is committing "imperceptible murders", meaning that the killer is choosing victims who are already dying therefore meaning that the police would be less likely to suspect foul play.
Martin goes to the hospital where his girlfriend Lorna (Leonor Watling) works. There he meets a religious fanatic (Dominique Pinon), who has a daughter in dire need of a lung transplant. He also runs into Seldom, who is visiting Kalman (Alex Cox), a former student who went mad and suffers from a debilitating cancer, with bone involvement. Soon after, the patient who shares the room with Seldom's friend dies of an apparent lethal injection and the authorities receive a second symbol: two interlocking arcs.
Martin and Lorna's relationship becomes strained as he becomes more obsessed with Seldom and the murders and discovers that Lorna had once been Seldom's lover. At a Guy Fawkes Night concert, Martin sees Podorov acting suspiciously and the police give chase, only to discover that Podorov had merely intended to hang an insulting banner from the school roof. While they are distracted a member of the orchestra collapses and dies from respiratory failure. A drawing of a triangle is found on his music stand. Afterwards, Seldom tells Martin a story about a nineteenth century man who had written a diary listing ways to kill his wife. When the wife discovered the diary she killed her husband but was acquitted by a jury on grounds of self-defense. Decades later, the diary was discovered to have been forged by the woman's lover. Seldom uses this story to explain that the perfect crime is not one which is never solved, but one which is solved incorrectly.
All of Oxford's mathematics community is excited as a local researcher claims to have solved Fermat's last theorem. The mathematicians, including Seldom and Martin, board a bus to head to the conference, but Martin jumps out after seeing Lorna passing on the street. The two reconcile and agree to take a long vacation away from Oxford, mathematics, and Seldom. After making love with Lorna, Martin realizes that the sequence the killer has sent them all consist of Pythagorean symbols and that the fourth one will be a tetractys, consisting of ten points.
The police, thinking that the killer is obsessed with Seldom, believe that he means to target the bus which Seldom and the other mathematicians are on. However, the killer, as Martin realizes, is actually the man he had met at the hospital. The man is a bus driver for a school for developmentally disabled children. Seeing the students as unfit to live and wanting to provide organ donors to save his own daughter's life, he blows up his bus, killing the children inside and himself. Afterwards, the police theorize that he had planned to escape the blast alive and had committed the other murders in order to present the deaths of the schoolchildren as the work of a serial killer, thus shifting blame from himself.
Afterwards, Lorna and Martin prepare to leave Oxford. However, Martin realizes that Seldom has been lying to him the entire time. As Lorna leaves in disgust, Martin travels to meet Seldom. He explains what he has figured out.
Beth, wanting to be relieved of the responsibility of caring for her mother, had murdered the old woman as the police had initially suspected. In a panic, she had called Seldom, who came over to help cover up the crime. But Seldom arrived just as Martin did and so could not clean up the crime scene. Instead, he invented the story about receiving a note from the killer in order to throw suspicion off of Beth. The man at the hospital had died of natural causes with Seldom merely creating a fake injection mark and leaving a symbol behind. The death of the musician at the concert was a fortuitous accident which Seldom took advantage of.
Seldom argues that while he did indeed lie, his actions resulted in no deaths. However, Martin points out that the bus bomber took his inspiration from Seldom's string of murders. Seldom counters that all actions have unintended consequences and that Martin's flirtations with Beth had led to her murdering her mother.