Now, you'll have to help Luigi track his brother down, making your way through expansive 3D levels. Of course, his feelings immediately shift when his brother, the storied Mario, disappears from the house. When Luigi learns that he's the proud new owner of a creepy old mansion, he's thrilled. In Luigi's Mansion, Luigi steps out from the shadow of his brother Mario and into the gloomy shadows of a very haunted house in this, his first-ever starring role.