The Tunnel is set against the backdrop of Europe in crisis. When a prominent French politician is found dead on the border between the UK and France, detectives Karl Roebuck (Stephen Dillane, Game of Thrones) and Elise Wassermann (Clémence Poésy, Harry Potter and the Deathly Hallows Part II) are sent to investigate on behalf of their respective countries. The case takes a surreal turn when a shocking discovery is made at the crime scene, forcing the French and British police into an uneasy partnership. As the serial killer uses ever more elaborate and ingenious methods to highlight the moral bankruptcy of modern society, Karl and Elise are drawn deeper into his increasingly personal agenda.
When Karl and Elise reach a dead end in the case, they both resort to unconventional means in pursuit of the truth. With the body count rising, the stakes could not be higher - but will their gambles pay off?