After the police have raided a man's home for illegal guns, they don't realise that they haven't collected two of them. When the man is released on bail he returns home, gets one of the guns and returns to the station where he murders one of the officers involved in the raid.

A mysterious ad appears in the newspaper with the words "Ars Morendi". A group of people meet in a secret location to bet on the outcome of 'Russian Roulette' games where a person's life is at stake.