Luigi won a mansion — or so the letter said. Thrilled, he called Mario, arranged to meet, and set off with a map. But the forest grew dark, the path twisted, and by the time Luigi found the mansion at the edge of the woods, his brother was nowhere. The place was full of ghosts instead. When one lunged at him, a peculiar old man with a vacuum cleaner strapped to his back appeared out of nowhere and pulled him to safety. That man was Professor Elvin Gadd, a ghost researcher who lived nearby. Hearing that Mario had gone missing, Gadd handed Luigi two inventions and sent him back inside. Luigi is not known for bravery. But Mario is not going to find himself.