Homeless suspect Oliver Bartko is in police custody, panicking in his cell and rampaging. Investigator Maik Briegand can hardly bear to see his friend suffer. Against all regulations, he takes him outside so he can calm down. When Maik's colleague Annalena wants to take Oliver back to the cell, the situation escalates, with dire consequences.

The LKA investigators Maik Briegand and Annalena Gottknecht put Florian Langendorff, the friend of Maik's ex-wife, under pressure during the interrogation. Finally he admits that the murder victim Ramona sold him coke. But he denies killing her.

The publications about Ramona's death shocked Maik Briegand's father Karl, who was also a police officer. 30 years ago he investigated the "Katti" case. She was his son's childhood sweetheart and died under mysterious circumstances. Maik wants to know from his father why he is now dealing with Katti's death again.