One day, Luigi received an unexpected message: You've won a huge mansion! Naturally, He[sic] got very excited and called his brother, Mario. "Mario? It's me, Luigi. I won myself a big mansion! Meet me there and we'll celebrate, what do you say?" Luigi tried to follow the map to his new mansion, but the night was dark, and he became hopelessly lost in an eerie forest along the way. Finally, he came upon a gloomy mansion on the edge of the woods. According to the map, this mansion seemed to be the one Luigi was looking for. As soon as Luigi set foot in the mansion, he started to feel nervous. Mario, who should have arrived first, was nowhere to be seen. Not only that, but there were ghosts in the mansion! Suddenly, a ghost lunged at Luigi! "Mario! Help meee!" That's when a strange old man with a vacuum cleaner on his back appeared out of nowhere! This strange fellow managed to rescue Luigi from the ghosts, then the two of them escaped... It just so happened that the old man, Professor Elvin Gadd, who lived near the house, was researching his favorite subject, ghosts. Luigi told Professor E. Gadd that his brother Mario was missing, so the Professor decided to give Luigi two inventions that would help him search for his brother. Luigi's not exactly known for his bravery. Can he get rid of all the prank-loving ghosts and find Mario?