A can of crabs and some counterfeit coins lead Tintin to the ship "Karaboudjan," where he meets Captain Haddock under conditions of captivity. They join forces in their escape and for all subsequent adventures, ending up in the Sahara Desert and later in Morocco, where they dismantle Omar Ben Salaad's opium smuggling ring, which used cans that certainly did not contain crabs. However, Captain Haddock will do everything to quit alcohol, or at least reduce it...