| Director | Luc Besson |
|---|---|
| Budget | €197 million |
| Box office | $226 million |
In the 28th century, cooperation between the Earth and extraterrestrial species has expanded the former International Space Station to the point its mass threatens gravitational disruption to Earth. Relocated to deep space, it becomes Alpha, a space-traveling city inhabited by 3,236 species from hundreds of planets. Valerian and Laureline are partners in the United Human Federation police.
Valerian has a dream of the planet Mül, where a low-tech humanoid race fishes for pearls containing energy, which is converted by a small animal for use. A huge spacecraft crashes into the planet, causing an extinction event. The planet's princess, Lihö-Minaa, is stranded outside, but before she dies, she conveys an energy wave containing a telepathic message.
Valerian and Laureline are on a mission to retrieve the last Mül converter animal, which is in the hands of black market dealer Igon Siruss. In a marketplace on planet Kirian in an alternate dimension, Valerian disrupts a meeting between Igon and two hooded figures similar to the humanoids from his dream. They, too, seek the converter. Valerian and Laureline recover the converter, and Valerian steals an energy pearl. They learn that Mül was destroyed 30 years earlier, and information about it is classified.
Onboard Alpha, commander Arün Filitt informs them that the center of the station has been irradiated by an unknown force, rendering it highly toxic. Troops sent into the area have not returned and the radiation levels are increasing. Laureline and Valerian are assigned to protect the commander during an interstation summit on the crisis; against the commander's wishes, Laureline maintains possession of the converter.
During the summit, Mül humanoids attack and kidnap Filitt. Valerian chases the kidnappers to the irradiated area but crashes his spaceplane. Laureline enlists alien information brokers to find Valerian at the edge of the irradiated zone. She is kidnapped by a primitive tribe and presented as the choice course at their emperor's dinner. Valerian infiltrates the tribe's territory with the help of a shape-shifter named Bubble. Laureline and Valerian escape, but Bubble is fatally wounded. Valerian and Laureline venture into the irradiated area, discovering it is not dangerous and contains an antique spacecraft. They find the humanoids, the Pearls, with an unconscious Filitt.
Pearl Emperor Haban Limaï explains that his people lived peacefully on Mül until a battle occurred on their world between the Federation and a hostile alien race. The human commander Filitt ordered the use of fusion missiles to destroy the enemy mothership, but inadvertently resulted in Mül's destruction. Upon her death, Princess Lihö-Minaa transferred her soul into Valerian's body. Haban and some of Mül's inhabitants survive in a previously crashed vessel. Trapped in the spaceship, the surviving Pearls repaired it and learned human technology and history. Scrap ships took them to Alpha, where they assimilated knowledge from different species and built their own ship. They need the converter and pearl to launch it, so they can find a new home.
Filitt admits his role in the genocide but argues it was necessary to end the war and cover it up to prevent humans from losing credibility and influence in Alpha. Valerian and Laureline argue that the commander is trying to avoid the consequences of his actions. When Filitt becomes belligerent, Valerian knocks him out.
Valerian hands over the pearl he took from Igon, and Laureline persuades him to return the converter. While the Pearls prepare their spacecraft for takeoff, Filitt's K-Tron robot soldiers attack them, but Valerian and the surviving government soldiers defeat the robots. The spacecraft departs, and Filitt is arrested.
Valerian and Laureline are left adrift aboard an old space ship, where she answers his marriage proposal with a "maybe" as they await rescue.
Although the overall plot does not follow any specific volume of the original Valérian and Laureline graphic novels, much of the action of the film was adapted from the seventh volume, L'Ambassadeur des Ombres ("Ambassador of the Shadows"). in which Laureline searches through the enormous space station Point Central (called "Alpha" in the film), a meeting point of thousands of alien species with multiple different environments, to rescue Valérian, who is lost somewhere in the space station while chasing after the kidnappers of an ambassador who has been abducted by an unknown species. The title of the film echoes the title of the volume "Empire of a Thousand Planets," but does not follow the plot.