Eight-year-old Samuel Wiese feels very lonely since his father left the family a year ago to work as a doctor in Afghanistan. Particularly important to him now is his little golden hamster Raffi, whom he got from his dad and who has some amazing tricks up his sleeve, such as scoring goals in his cage. Sammy is correspondingly shocked when Raffi is simply kidnapped one day after a heart operation. Shortly decided and without telling his mother Helene or his older sister Molly about it, he sets out alone to find his little friend again in the big Hamburg. But how do you find a hamster in a metropolis with a good 1.7 million inhabitants?