Luigi, Mario, Princess Peach, and a group of Toads accept an invitation to vacation at The Last Resort, a grand Art Deco hotel located in a remote mountainside area. Shortly after arriving and settling in for the night, Luigi awakens to find the hotel transformed into a haunted building and his companions missing. He discovers that the hotel's ghostly owner, Hellen Gravely, orchestrated the entire invitation as a trap on behalf of King Boo, whom she freed from captivity. King Boo reveals his plan to imprison Luigi and his friends in portraits as revenge for his previous defeats. Luigi narrowly escapes to the basement, where he finds Professor E. Gadd's equipment and frees the captured professor. Together they learn that Luigi's friends are being held somewhere on the hotel's upper floors. Armed with a new Poltergust vacuum device and aided by Gooigi, an ectoplasmic duplicate of himself, Luigi must ascend through the hotel's many themed floors, recovering stolen elevator buttons from powerful ghosts to reach his trapped companions before King Boo's plan succeeds.