Shortly after the events of Mario Odyssey, Cappy and Tiara return to Bonneton to welcome the townsfolk. A big surprise is that the airships are back in the air, and they're ready for international travel. Cappy then agrees to help them set up the B.T.A. (Bonneton Travel Agency) by collecting Power Moons to power airships.
So Cappy guides the airship with his own ship. You play as Cappy spending about 5 minutes in each of the 14 kingdoms maintaining the B.T.A. airport progress. Every time the airport finishes you move on to another kingdom.
Around the middle of the game, the airships get shot down, requiring Cappy to find the power needed to repair the airships. Then it continues normally from there.
After finishing the Moon Kingdom, the B.T.A.s are finally complete, allowing you to go back to other kingdoms and free-roam the game. The game doesn't really end until you've gotten all the moons, whicheach kingdom has half of the same moons from Super Mario Odyssey, and half of them are unique.
Sometimes you'll be talking with civilians, sometimes you'll be platforming
L stick - Move Cappy / Choose Option
R stick - Rotate camera
Ⓐ - Jump / Pick Option
Ⓑ - Jump / Back
Ⓨ - Dash / Speed up text
Ⓧ - (around capturable object) Capture Object / Auto text
ZL/ZR - Crouch