The Mario Brothers are now famous. One day, Luigi gets a letter telling him he won a mansion, from an unknown sender with the initials KB. Curious, he follows the directions to find a large, green dirty mansion in the middle of nowhere. He reluctantly steps through the towering doors into the lobby. There, he see's Toad cowering in the middle of the room. Luigi tells him it looked like he had seen a ghost, and Toad replies 'I did.' much to Luigi's confusion. Whilst exploring the lobby, Toad finds a secret tunnel behind a painting of a round white ghost with a crown. Toad explains to Luigi that the creature is a Boo, a type of rare ghost. They go through the tunnel which leads them to some type of shack. Once in the shack, they spot a strange man wearing a lab coat. The man notices them, and is confused. He asks how Luigi escaped from King Boo. Confused, he tells the man he has no idea who King Boo is. The man realizes his mistake and apologizes. He tells them how a man wearing red and a mustache was taken hostage by King Boo. Luigi tells him that was his brother Mario. The man then introduces himself as Professor Elvin Gadd. He explains his job. Gadd is a scientist who researches ghosts and observes them by trapping them in paintings. He points to a room filled with empty frames. Toad notices a specifically large one and asks what it is. Gadd tells him it belonged to King Boo. Suddenly, an orange ghost breaks in and starts destroying everything. Panicking, Luigi picks up a random machine and pulls the trigger. The ghost gets sucked into the machine, and fades into nothingness. Elvin see's this, and decides to train Luigi how to use the machine. Eventually, Gadd feels Luigi is ready to use 'The Poltergust 3000' to find King Boo and rescue Mario. He also gives Toad a much smaller early design of The Poltergust, which he names 'The Poltergust Beta'. They fight through different floors, each with strange ghosts. On the 3rd floor, they see a strange looking café. Toad drinks a liquid which was apparently poisonous. Luigi finds a note saying that the poison takes effect exactly two hours after being drank and the only thing that can heal the drinker is the liquid of a crown, again signed by KB. Luigi, and a now very weak Toad, encounter King Boo on the 5th floor. He summons several Boo's to do his dirty work. He says his 'partner in crime' told him about Luigi. After fighting off the ghosts, Luigi realizes he only has a half hour before the poison takes place. He fights his way through the attic, and finds a rope bound unconscious Mario. He rushes towards him, only to be ambushed by King Boo. King Boo disintegrates the mansion and summons a platform that lifts hundred of feet in the air. Mario's neck is around a hangman's noose and Toad's existence is literally fading away. After a long dreary fight, King Boo is defeated. Mario is saved. King Boo's crown smashes revealing a liquid. Luigi gets Toad to drink it seconds before he fades into nothingness. Luigi goes back down to the bottom floor to be greeted by Gadd. They bid a goodbye and promise to keep in touch. Luigi gives Gadd all the ghosts he had caught, which Gadd happily accepted. A few months afterwards Luigi gets another letter from Gadd. He is told to go to a hill. On the hill, he finds an extravagant new mansion. Gadd explained in the letter, he had used the money he earned to pay Luigi back with a new mansion. He happily moves into the home, with his pet.
2 hours 6 minutes 37 seconds.
- Charles Martinet as Luigi and Mario
- Samantha Kelly as the voice of Toad
- Kazumi Totaka as Professor Elvin Gadd Ph.D.
- Toru Asakawa as the voice of King Boo
- Lani Minella as the voice of The Orange Ghosts
- Jim Cummings as the voice of The Black Ghosts
- Mike Vaughn as the voice of The Blue Ghosts
- Maurice LaMarche as the voice of The Purple Ghosts
- Tara Strong as the voice of The Green Ghosts
13 months after the theatre release, the director Joss Whedon told fans that a "Dark Moon" was on the rise. Many fans believed this to be The Luigi Movie 2. 3 months afterwards, Charles Martinet, who plays Luigi, told them that "a new mansion is being built.". Another 2 months afterwards, Joss Whedon officially announced The Luigi Movie: The Dark Moon.