When drugstore owner Geelman's watch is missing, he accuses incorrigible rascal Pietje Bell. The boy is thrown in jail without trial, but quickly escapes and is proved innocent. During his short prison stay he meets gangmate Willem Sproet's dad Jan Lampe, who wants to resume contact, and crimelord Stark, who buys himself a luxury regime in jail and keeps organizing crime from within. Pietje mobilizes his 'Robin Hood'-type Black Hand gang. He also causes havoc at a party to 'punish' his sister Martha's lover, well-meaning newspaper owner Paul Velinga, and gets abducted to be extorted in jail solitary by Stark. That opens the way for Geelman's son Joost, which Pietje and his gang must prevent. Meanwhile, Stark plans to have a Russian czarist crown stolen from a visiting exposition, but Pietje is tipped off.