An elderly woman is viciously murdered in the city of Oxford. Her murder becomes "the first of a series" linked by a cunning twist of logic. Arthur Seldom (Academy Award winner John Hurt, Harry Potter Series), a prestigious professor of logic, and Martin (Elijah Wood, Lord of the Rings Trilogy), a young graduate student join forces and apply all of their mathematical skills to solve the grisly crimes. As Seldom is an authority on logical series, he suspects that a serial murderer is defying his intelligence, murdering his friends one by one in a gruesome attempt to challenge his theories and academic stature. It is up to Martin, Seldom and Spanish nurse Lorna (Leonor Watling, Talk to Her) to try and crack the code, setting into motion an elaborate game with ever-increasing stakes. As Martin gets closer to the truth, his world of cryptic discovery becomes all the more unsettling and unnerving.