The actor you'll most likely recognise is Will Poulter (The Maze Runner, We're the Millers, The Little Stranger), who plays Stefan's coprogrammer, Colin. Stefan himself is played by Fionn Whitehead, of Dunkirk fame. Rounding out the rest of the cast is Line of Duty's Craig Parkinson as Peter, Prevenge's Alice Lowe as Dr. Haynes, and People Just Do Nothing star Asim Chaudhry as Tucker.