The film incorporates characters and events from several of the albums, in particular the first, "Adèle and the Beast", first published in 1976, and the fourth, 1978's "Mummies on Parade," within an overall plot of Besson's construction and takes place primarily in Paris,. While experimenting with the telepathic techniques he has been researching, Professor Espérandieu hatches a 136 million year-old pterosaur egg within the Galerie de paléontologie et d'anatomie comparée, resulting in the death of a former prefect which though witnessed only by the then-drunk Choupard sparks an epidemic of claimed sightings of the creature. The President of France orders the case be considered of utmost urgency by the National Police, only for it to be handed down to the bumbling Inspector Albert Caponi. Adèle Blanc-Sec, a journalist and travel writer of some fame, finds herself involved after returning from Egypt, where she was searching for Ramesses II's mummified doctor/physician Patmosis. She wants to revive the mummy with the help of Espérandieu so the doctor can save her sister Agathe, who is comatose following an unfortunate tennis incident involving a hatpin. After a brief struggle with her nemesis, the mysterious Professor Dieuleveult, she retrieves the mummy and returns home. Her mission is complicated further by Espérandieu being on death row, having been blamed for the pterosaur's attacks, in lieu of Inspector Caponi and celebrity big game hunter Justin de Saint-Hubert having any success in taking down the beast itself. Andrej Zborowski, a researcher at the Jardin des Plantes who is enamored with Adèle, is able to lure the pterosaur into hiding. Adèle, riding the pterosaur, rescues Espérandieu moments before his execution. Saint-Hubert fatally shoots the pterosaur along with Espérandieu, but not before Espérandieu is able to revive the mummy. The mummy reveals itself to be the Pharaoh's physicist and is unable to help her sister medically. He does, however, accompany Adèle to the Louvre, where they revive the rest of the Pharaoh's mummified court on display there, including the Pharaoh himself. The Pharaoh's doctor uses their advanced medical techniques to revive Agathe. The Pharaoh then decides he wants to see Paris, so the entire court wanders out into the night, scaring the ever-hapless Choupard yet again. Adèle decides she needs a vacation to relax. The final scene shows her boarding a ship, and the camera pans out to reveal the name of the ship, the RMS Titanic. Dieuleveult is then shown, maliciously smiling. In a mid-credits scene, Ménard pursues Saint-Hubert with a rifle, still outraged that Saint-Hubert shot the pterosaur. Ménard is arrested by Caponi as two gorillas stare menacingly at Saint-Hubert.
The film received positive reviews. Rotten Tomatoes gives the film a score of 84% based on reviews from 25 critics. Variety magazine called the film a "polished comicbook adaptation" and praised the performance of Louise Bourgoin's as the titular heroine. The reviewer complains that Besson's work is uneven, and the reviewer suggests that Besson would benefit from fresh collaborative voices, and a scissors for the overlong third act. Angie Errigo of Empire magazine gave the film 4 stars, proclaiming that "Besson is back". Matthew Turner of ViewLondon gave the film 5 stars, writing: "impressively directed and beautifully designed, this is a highly entertaining and frequently funny action-adventure romp with a witty script, great special effects and a terrific central performance from rising star Louise Bourgoin".
