This takes place after Luigi's Mansion 3.

Over the past couple of days, Luigi started noticing thing. Like how Mario was always seen as the brave one, the heroic one. But he is thought as cowardly. But he wasn't bothered, he was happy for Mario! He does do a lot more to be honest.

But these thoughts spread, until he starts thinking flat out lies. He is kept up at night by these thoughts. The next day though, he found himself unable to move his body. He could still see. And what he saw, was none other than king boo! King Boo had been putting those thoughts into his head to get him to a state of weakness! And possessed him overnight!

But King Boo wants the ultimate revenge. So he decides. Why not get rid of Mario, as Luigi? Luigi would be forced to watch and do nothing and Mario would feel betrayed. It was perfect. So as Mario was about to exit the last ghost house, King Boo made his move.

But at the end of the song (the song hasn't finished, it's just at the end), King Boo let's a laugh slip and Mario realises that it's King Boo!

*Cliffhanger noises.*

To be continued in the second song.