The Dark Moon that hangs over Evershade Valley seems to have a calming effect on the ghosts that reside there.
For this reason, Professor E. Gadd has been studying the friendly ghosts that are unique to the area. But when the Dark Moon suddenly breaks apart and falls into the valley below, the once-friendly ghosts become hostile, trapping E. Gadd in his bunker!
Luigi, who is at home watching TV, gets a big surprise when E. Gadd suddenly shows up on his TV screen and drags Luigi kicking and screaming through the screen into the Evershade Valley! After a little persuasion, Luigi agrees to help E. Gadd on his quest to find the Dark Moon pieces and restore it to its rightful place in the sky.