The wife of the underworld boss Lorenz wants to testify as a key witness. Tom and Semir provide escort on the highway for the BKA convoy in which Mrs. Lorenz is being transported. The route of the convoy was revealed, so she is suddenly ambushed by Lorenz's men. A group of killers carries out an attack in which the key witness only survives thanks to the courageous intervention of the two highway cops. Tom and Semir go into hiding with her. The BKA then asks for their help in further protecting Mrs. Lorenz. During their investigations, they discover that the BKA special task force that is supposed to protect the witness has been undermined by a mole. Tom's sister Nadja unexpectedly comes to visit. They are observed by Lorenz's men during this meeting. When Lorenz finds out about Nadja's visit, he has her kidnapped and gives Semir's partner a choice: either he brings Lorenz his wife or his sister must die.