The hitman Ralph Milan arrives in the city of Montpellier to eliminate witness Louis Randoni, who is soon to testify in a trial against the mafia bosses. Milan is a cold‑blooded professional who never misses. However, at the hotel, he runs into the loser François Pignon, which significantly complicates the situation, because the simple‑minded and annoying bore Pignon can drive even a hired killer with nerves of steel to distraction.