The Star Piece is guarded by the Czar Dragon, but after they defeat it and get the star, it is stolen by the Axem Rangers. Mario and his party chase the Axem Rangers through the volcano and end up on top of it, where the Axem Rangers get onto their huge battleship Blade, but are followed by Mario. Mario battles the Axem Rangers on Blade, defeats them and destroys the ship.
Halfway through Barrel Volcano, Hinopio is running an item shop, an inn and an armor shop. Many Frog Coins can also be found inside the volcano.
Inside Barrel Volcano