Mario and Meggy both finished the Fountain, and moved on to the next dome, the Kitchen. Ghostly Galaxy was their next stop.

Polari: Looks like one of your friends is inside. He looks like a green version of Mario.

Mario knew it was Luigi and was devastated by this.

Mario: Luigi! Please don't be tortured by ghosts.

Meggy: We gotta save him. I haven't seen one of our friends in days.

Mario: Don't you worry, Luigi. Meggy and I will save you and we'll be reunited soon.

They arrived at Ghostly Galaxy, and the first enemies they saw are a few Goombas with pumpkins on their heads.

Meggy: This is what they call spooky?

Mario: Yeah, you don't scare us. You die now.

Mario squashed the pumpkin Goomba, only to be burned by it's flame.

Mario: I'm burning! Why does the fire have to spawn in the same place as the thing I'm killing?

Meggy: I'll help you, Mario.

Meggy sets her gun to shoot water and sprays it at Mario, evaporating the flame.

Mario: Thanks, Meggy. (breathes) That's a spicy meat-a-ball.

They heard Luigi's cry for help from a distance.

Luigi: Help!

Mario: I'm-a coming for you, brother.

As they go through the twisted walkway to the mansion, they saw a Chain Chomp rolling towards them. They dodged it by going on these platforms on the sides.

They went inside the mansion, and came across a Boo. They weren't scared by him, though.

They saw a switch beside them. Mario pulled it and a light came from the ceiling. The Boo went towards the light, because him not being scary wanted him to end it all, and he vanished, leaving only a key.

They picked the key up, unlocked the door, and went inside the next room.

They explored the mansion until they saw two white mushrooms with Boo's faces on them.

Mario: What are these things?

Meggy: I don't know.

Meggy went over and touched one of them, and she turned into a Boo.

Meggy: (screams) Am I dead?

Mario: Calm down, Meggy. I got yo...

Mario accidentally ran into the other Boo Mushroom and turned into a Boo as well.

Mario: Oh Christ! It really is a spooky mansion.

Luigi: Help me!

Meggy: Maybe trying to save Luigi will take our minds off being Boos.

Mario: Yeah, good idea.

While flying around as a Boo, Meggy touched light and turned back to normal.

Meggy: Thank you. I never wanna be that again.

Mario: Hey, Meggy. Look at what I can do.

Mario turned transparent and went through a wall to advance.

Mario: Come on, Meggy. You need to stay as a Boo to go through this mansion.

Meggy: *sigh* Fine, I'll do it... for you.

Meggy went back to the Boo Mushroom, turned back into a Boo, avoided the light this time, went through the wall, and rejoined Mario.

The next room had a cage with Luigi inside.

Mario: Luigi! I found you!

Luigi: Ghosts! Eeeeek!

Mario forgot that he was a Boo as Mario thought of a way to turn back to normal. He and Meggy went inside the cage and touched the light inside. They returned to their normal selves and reunited with Luigi.

Mario: Luigi. I'm back! How did you escape?

Luigi: Mario, Meggy, you finally came! I escaped from the invasion back at the Star Festival and went with the rest of the Toads. I got lost with the group and ended up in this haunted mansion. It was terrible! Anyways, I found a Power Star for you.

Luigi gave the Power Star he found to Mario and Meggy, and they went back to the Observatory. Rosalina was waiting for them.

Rosalina: Welcome back. I can see your friend from here. If you ask him, I bet he'll help you search for Power Stars. And I'm sure he has a lot to tell you. You should go speak to him over there by the Garage.

Luigi was at the Garage with the rest of the Toads. Mario and Meggy went to talk to him.

Luigi: Mario and Meggy! You're looking for Power Stars, right? Let me help!

Mario: Oh, thank you! You're a good help, Luigi.

Meggy: Well, If we manage to return home to defeat SMG3 and Desti, will you help as well?

Luigi: Of course I will. Our friends are in danger, and our help is needed. See you around, you two. Keep looking for those Power Stars.

Mario: We will, Luigi. Thanks for your help!