Swiss Sigurd Willemsen gives young lawyer Katharina Tenzer an unusual assignment: 37-year-old Bernhard Fillinger has been living in Costa Rica for years, as he is a tax fugitive wanted under an international arrest warrant. However, he suffers from a terminal illness, and his only hope is a new therapy in Hamburg. Katharina is to negotiate a deal: in exchange for a suspension of his sentence, Fillinger is willing to disclose his knowledge about the missing East German money that vanished during the reunification. Given the potential 300 million that could flow to the state, the public prosecutor's office actually agrees to the deal. When Katharina goes to pick up her client at the airport, she initially only encounters his ten-year-old son, Ramon. Then the unimaginable happens: Fillinger is shot dead right in front of them from a moving car. Quickly, Kat.