A series of robberies at jewelry stores has the North City of Cologne on edge - and the thieves always mark the wall with a chalk shark. When twelve-year-old Wladi witnesses the theft of his own gold watch, he teams up with his friends Sema, Laura, and Kevin to track down the criminals. As always, the playground gang does everything to be faster than the police allow - and they find themselves caught up in a real estate scandal that threatens to take away many Cologne residents' homes. Is this case too big for them?.