In the 28th century, the Universe is home to Alpha, an ever-expanding metropolis where species from across the cosmos have converged over centuries to share knowledge, intelligence, and cultures. When a dark force threatens the peaceful existence of the City of a Thousand Planets, Valerian and Laureline, special operatives for the government of human territories, are assigned to maintain order and safeguard this melting pot of intergalactic societies. As they embark on their mission, the partners must navigate a complex conspiracy and a variety of alien worlds and beings.

Valerian and Laureline are tasked with retrieving a rare creature, known as the Converter, which has the extraordinary power to replicate anything it eats. The mission leads them to a marketplace in another dimension where they encounter an array of alien technology and lifeforms. Their operation sets off a chain of events that sends the pair on an action-packed journey filled with breathtaking landscapes and deadly adversaries. As they delve deeper into the mystery, they uncover a thread that ties back to the very existence of Alpha, and must race against time to identify the malevolent force that could corrupt the peaceful unity of the City of a Thousand Planets.