Li'l Quinquin has grown up and now goes by the name of Coincoin. His girlfriend, Ève, has left him for another girl, Corinne, but he continues to run wild with his friend, Fatso. One day, in a field, he discovers a strange black magma that seems to have fallen from the sky. As Inspector Van der Weyden and his loyal assistant Carpentier investigate, new "extra-human" events occur.
