In the 28th century, Valérian and Laureline form a team of spatiotemporal agents responsible for maintaining order in the human territories. Mandated by the Department of Defense, the duo sets out on a mission to the extraordinary intergalactic city, Alpha - a constantly expanding metropolis where species that have come from the entire universe have converged over the centuries to share their knowledge, expertise, and culture. A mystery lurks at the heart of Alpha, a dark force that threatens the peaceful existence of the City of a Thousand Planets. Valérian and Laureline must undertake a race against the clock to identify the terrible threat and to save not only Alpha, but the future of the universe.