Mario and Meggy arrived at the Comet Observatory, where Rosalina is waiting for them.

Rosalina: Welcome to the Comet Observatory. It's my home, and also home to the Lumas.

Mario: Are you gonna tell us a long story about your past? Because we need to get ba...

Rosalina: You see...

Mario: Goddamnit.

Rosalina: ...we travel the starry skies. We pass by this area once every one hundred years, but we suddenly stopped in front of this planet. A strange force had latched on to our ship, pulling away Star Bits and our power source, Power Stars. Our ship had lost power, so it entered a deep hibernation state in which it could not move. Those who took over your home picked up the Power Stars and discovered the power to cross the universe.

Meggy: So it was those two who made your ship unable to move.

Rosalina: Please, I have a request...

Mario: *sigh* What is it, space lady?

Rosalina: This observatory uses Star Power to project images of the galaxies that are scattered across space. And... there is a chance we can use our few remaining stars to look for other Power Stars.

Mario: Well, If getting back home requires collecting stars or other shiny things, then I'll help out.

Rosalina: These round rooms are called domes. We observe galaxies from domes such as these. But the only one that is working now is the Terrace over there. Please go to the Terrace and try to recover the Power Stars from the galaxies you can see from there.

A black Luma was beside her. It's name was Polari.

Polari: If we do that, we'll be able to restore the Comet Observatory's ability to fly like a starship. Then perhaps we can pursue the thieves who ran off with the Power Stars.

Mario: And return home?

Polari: Yes.

Meggy: Well, we'll promise to help you out so we can get back home and stop these two villains. You ready, Mario?

Mario: Well, what are we waiting for? Earth isn't gonna move itself.

Mario and Meggy went inside the Terrace, as they saw Polari was already waiting for them.

Mario: How did you get in there? We saw you outside.

Polari: Teleportation.

Mario: Oh. Makes a whole lotta goddamn sense.

Polari: Anyways, welcome! This dome acts as an eye of the observatory. From here, we can gaze upon different galaxies.

Mario: So what's the first galaxy we can go to?

Polari: Good Egg Galaxy.

A Launch Star leading to the galaxy appeared.

Mario: So, Meggy. You ready for a possibly long journey collecting a ton of Power Stars?

Meggy: Of course I am.

Mario: Okie-dokie. Here we go!

Mario and Meggy span together and flew to Good Egg Galaxy.

Meggy: You know, flying through space kinda feels romantic, don't you think?

Mario: Well, we're holding hands, so I guess it counts.

Meggy pulled Mario in for a kiss because she just wants to, and Mario went with it.

After their kiss, they arrive at Good Egg Galaxy.

Once they arrived, they noticed that there are Star Bits here as well.

Mario: Man, I am starving. I'm glad that Star Bits are here.

Meggy: We gotta have some food once in a while, so complementary Star Bits falling down from the sky will sure fill up our appetite.

After a few minutes of eating Star Bits and trying to find the star on the planet, the come across a yellow Luma on the other side.

Yellow Luma: My friends are ahead. Hurry!

The Luma turned into a Launch Star, as Mario and Meggy spun and flew into the next planet, which had boulders rolling in many places.

They saw a Star Chip and Mario picked it up.

Meggy: I see some more of those things across this planet.

Meggy picked up the second Star Chip, as she was close to getting hit by a boulder.

Mario: Look out, Meggy!

Mario pushed Meggy out of the way as he got crushed by the boulder, flattening him.

Meggy: Mario...

Mario: It's okay. I'm fine.

Mario went back to his normal shape.

Mario: I have been crushed many times before, and I still turn out fine.

Meggy: Well, let's get the rest of those things.

Mario and Meggy collected the rest of the Star Chips, as they turn into another Launch Star, and they spin into it.

On the next planet, they are faced with a Piranha Plant, and Mario then jumped on it.

Mario: This is for taking Waluigi's spot in Smash.

The Piranha Plant then grew a long vine, as Mario and Meggy climbed it and went to the next planet.

A few planets later, they saw that their next location has a giant egg on top, and they landed on the egg, cracking it a little.

Legs and a tail were coming out of the egg, showing that some monster is inside.

Meggy: Mario. I think that thing we just woke up isn't too happy. I think we should leave this guy alone.

Mario: And lose the chance of winning a star and getting one step closer to home? Screw this. I'm killing him.

Mario hit the tail with his spin attack, which caused it to hit the egg and crack it open, revealing the monster who's inside the egg. Dino Piranha.

Meggy: Mario. You're right. Let's kill him.

Mario: How about you land a hit on him?

Luma went out of Mario's body and into Meggy's, as she spun and hit Dino Piranha's tail, which sprung back and hit Dino Piranha.

Mario and Meggy each got another hit on Dino Piranha, as it screams and falls down on the ground, disappearing as the first star came out.

Mario and Meggy grabbed the star together and celebrated.

They talked to each other as they flew back.

Mario: So we also should be ready for fighting with bad guys along the way.

Meggy: Hopefully this whole adventure would be worth it for a trip home.

Mario: I hope so too.

Mario and Meggy continued on with their galaxy adventure.