Xavier Marechal (Alain Delon) is a businessman whose long-time business partner and friend is Philippe Dubaye (Maurice Ronet) a member of the French parliamentary assembly. In the film, Philippe has just killed Cerrano, a fellow assemblyman who threatened to disclose Philippe's involvement in political corruption. After killing the man, he steals his notebook which contains blackmail information implicating many members of the government. Philippe comes to Xavier afterward for help but only has time to tell him where the notebook is hidden before he is killed. Xavier and Philippe's girlfriend Valerie (Ornella Muti) become the objects of a manhunt by the worried politicians and their henchmen. Mort d'Un Pourri was basically an Alain Delon project; he funded the production of this action thriller, lent his name to it, and invited well-known action- and comedy-director Georges Lautner to direct it. This virtually guaranteed enough money for a polished production, with an all-star cast. Alain Delon here remains faithful to his image as a lone wolf, proud warrior and "samurai" devoted to friendship.
by Clarke Fountain synopsis