Hamburg: Single Martha lovingly cares for the children in her neighborhood, supported by ex-boxer Max. One day, the withdrawn Tommy Skagen moves into Martha's apartment block together with his eight-year-old brother Winnie. Tommy, who studies law at daytime, often disappears for nights on end, leaving his brother alone. Illegal mixed-martial-arts fights take place in the docks below St. Pauli. Here - for high stakes - fighters compete against each other without boxing gloves or head protection. Tommy is one of them. He loves the fight and he needs the money. But his double life visibly overwhelms him. When one day Viktor Skagen shows up to reclaim custody of Winnie, Martha begins to get actively involved. Cautiously, Martha and Tommy grow closer. Tommy begins to suspect that Martha also has a secret, which she carefully hides behind her equally impressive and friendly facade.