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.

Back in Amsterdam, there is still no trace of the van with mustard gas. In the meantime, the city is full of protesters. De Cock and Ruiter do everything in their power to prevent an attack.