Udo is invisible - no one ever seems to notice him. He makes the most of it, working as a department store detective and living off other people's lives as they never notice him tagging along. Until he meets the one woman who sees him.

Deputy director Sonja Winter is fighting against the closure of "her" zoo, where she lives with her daughter Hanna. However, city councillor Antonia Grewe is determined to push through her plan. Her right-hand man is, of all people, the architect Mark Fechter, whose eight-year-old son Tom is Hanna's friend. When Hanna learns that her old friend "Schulze" is to be put to sleep as part of the lockdown, she and Tom decide to kidnap the penguin...