In the twenty-eighth century, space station Alpha is a city where beings from different planets live together exchanging their knowledge and culture. Peace is maintained by human agents Valerian and Laureline, who are sent on a dangerous mission to retrieve the last specimen of a converter. Back on Alpha, a group of unknown humanoids abducts Commander Arun Filitt, and Valerian and Laureline follow them into a forbidden contaminated area, where they uncover a hidden secret about the race and the infected zone.