While fishing in the North Sea, eleven out of the twelve men of the Lutèce, a fishing-boat from Concarneau, get intoxicated after having eaten rotten ham. The only one unscathed is Mohammed, a Muslim who does not eat pork meat. The situation is serious for the eleven victims : if they do not get a serum quickly they will die. Luckily Captain Le Guellec has had time to send an S.O.S. which is picked up by Jean-Louisa young radio ham.