Sarah Kohr is pursuing a man whom she had enabled to participate in a witness protection programme decades ago. That's why Nils Köppke has no business being in Hamburg since he testified against his brother Sven, who swore revenge. The brothers once recovered suitcases full of gold and jewels with the explosive ‘Köppke method’ of the explosives specialists. So why is he back in town?

According to the contacts, the key witness has built a righteous life in a city in Bavaria over the last decade, after completing his studies in structural engineering there. A happy life, not long with a new partner. How strong does the motive have to be to give all that up again? Could the brothers have reconciled? Sarah investigates Nils's surroundings and finds out that big brother Sven has been released from prison early. According to the prison doctor, he doesn't have long to live and is allowed to live out his final days in freedom for humanitarian reasons. Is blood really thicker than water, or is Nils acting out of love for his girlfriend or out of fear, or perhaps both? Sarah is then able to prevent a break-in at a museum in Hamburg. But when the perpetrators flee, they manage to take her hostage...