During a chase on the highway, the professional killer "Joker" is killed in a taxi. André and Semir find weapons in the dead man's luggage. It quickly becomes clear that Joker was commissioned to carry out a murder and that the client is looking for a new killer. Without support from the BKA, André and Semir investigate independently. Semir goes undercover as a professional killer to expose the client, but the plan fails and his life is in danger.