A mysterious nighttime Berlin, a murder, a love story. Daniel Stillmann, a seventh-semester mathematics student, dislikes problems that have exactly two contradictory solutions. When he witnesses a crime at the Admiralsbrücke in Kreuzberg, the cold logic of his formulas fails him. He faces a great unknown, spiraling into fear and increasingly dreading living someone else's story. This is how Marlies and the first-person narrator have conceived it, driving their character Daniel into the eerie grip of an old man, until one day Marlies mysteriously disappears as well. In this case, the boundaries of gender prove to be as unreliable as the laws of space and time.