The plot follows detectives Karl Roebuck and Elise Wasserman working together to find a serial killer who left the upper-half body of a French politician and the lower-half of a British prostitute in the Channel Tunnel, at the midpoint between France and the UK. They later learn that the killer—who comes to be nicknamed the "Truth Terrorist"—is on a moral crusade to highlight many social problems, terrorising both countries in the process

Stephen Dillaneas Karl Roebuck
Clémence Poésyas Élise Wassermann
Thibault de Montalembertas Olivier Pujol
Tobi Bakareas Chucks Akinade
Joseph Mawleas Stephen Beaumont
Tom Batemanas Danny Hillier
Sigrid Bouazizas Cécile Cabrillac
Cédric Vieiraas Phillipe Viot
Angel Coulbyas Laura Roebuck
Jack Lowdenas Adam Roebuck
Chris Lang