As an anthology series, each episode is a self-contained science-fiction story taking place in a different world, with different characters played by a different cast and adapted from a story previously published in the Métal Hurlant magazine. However the show also proposes that all the stories are linked together by a meteorite, called the "Métal Hurlant", which is passing close to the planet where the episode's story is taking place.
Metal Hurlant Chronicles - Pledge of Anya Synopsis and Schedule