Mezieres, J.C.; Christin, P.; Tranle, E. Valerian and Laureline: Chatelet Station Destination Cassiopeia; Cinebook, Cantebury, Kent, 1980. Kindle AZW file.

Mezieres, J.C.; Christin, P.; Tranle, E. Valerian and Laureline: Brooklyn Line Terminus Cosmos; Cinebook, Cantebury, Kent, 1981. Kindle AZW file.

Valerian and Laureline are two agents with the Spatio-Temporal Agency. Their assignment is to figure out why and how a series of creatures are appearing on Earth in 1980. In Earth's original history, there is no indication that the creatures existed, which makes it clear that the creatures are actually appearing from some future point in time. Valerian takes his place on Earth during 1980 when the creatures are actually appearing, while Laureline works on the case from space in a futuristic point in time.

Valerian works with an Earth agent named Albert who actually belongs and lives in 1980. Albert is something of an understated character. He is an older gentleman who is slightly overweight and always wears a jacket and tie. He is never willing to go with Valerian when Valerian is actually fighting the entities. However, he is extremely well-connected with friends all over the world who have knowledge and information that helps solve the mystery. He is an intelligent man who puts clues together to lead Valerian to be in the correct places as events are happening.

Meanwhile, Laureline is traveling to several futuristic points in space. She follows clues to the planet of Solum where a city is literally sinking into the ground. The inhabitants there constantly build new stories atop the old. Each story had a creature that is in charge of the memories of his time on top of the surface. Laureline descends 372 levels to find the story of a planet that experienced the appearance of a similar group of creatures to those who have appeared on Earth. She learns that the planet Ohuru blew up after similar creatures appeared, and that it was somehow linked to a theft on Zomuk, a planet where the entire galaxy disposes of its trash. On Zomuk, Laureline deals with horrific conditions to discover that two aliens stole the sacred treasures from a shrine. The treasures were the four elements – earth, wind, fire, and water.

Laureline tracks down the two aliens just as Valerian and Albert discover that two huge industrial firms have gathered in New York where they expect a demonstration of another creature. The firms actually want to purchase the technology from the aliens who stole it, and they hope to further their business endeavors with that technology. Valerian and the people of Earth are at a loss of how to stop or explain what is happening. However, Laureline tricks the two aliens into killing each other. Then, she destroys the four elemental items, bringing an end to the situation.

Valerian says his farewells and heads to the Statue of Liberty, where he knows there is a teleport that will take him back to his own time.