LaCroix wants De Cock to investigate the missing weapons in secrecy. With some reserves, De Cock calls her in for help with the interrogation of crown witness Willem Kroos.

There is chaos in the city when suddenly every teenager seems to hold a weapon. De Cock's distrust of his colleagues increases when crown witness Hassan is kidnapped and killed.

Looder visits the Warmoesstraat office. Wormgoor has mustard gas and is looking for a buyer. The hunt leads De Cock and Ruiter to Belgium, where they try to intercept the mustard gas.