- Police Guy
- King Boo
- King Bob-Omb
- Petey Piranha
- Troop Sr. ; first named appearance
- Troop Sr.'s wife
- Chain Chomp
- Lemmy Koopa
- the other six Koopalings
King Boo, still dictating the Mushroom Kingdom, is seen drinking a can of Pepsi, then later throwing it in a bin full of empty cans. King Bob-Omb is talking to Petey Piranha, saying that everybody in the Mushroom Kingdom have been getting addicted to Pepsi. Even Petey grabs a can and plunges the whole thing down his throat, including the can.
Meanwhile, Tiarer comes up to Berinda, saying that Rievoah barely brushes her teeth and has had a lot of sugar rushes. Police Guy then knocks on the door, asking them if they can help defeat King Boo. Tiarer says it is dangerous, and Police Guy understands. He then grabs two Pepsi cans and starts drinking them. Berinda then sneaks out of the house to a stall. She then steals some Pepsi cans, but gets caught by Police Guy. Her father, Troop Sr., in his first named appearance, forces her to pay with her pocket money.
Meanwhile, Bowser watches over the Mushroom Kingdom, wondering what they are going to do. Lemmy says that while the others are defeating King Boo, he will sneak behind and steal his magic wand and hypnotise everyone to become their slaves. Bowser thinks this is a great idea and tells Lemmy to do it.
Toadette and Toadokay decide to enter King Boo's castle. They manage to sneak into a secret room, since the guards are too busy drinking Pepsi. Inside the room, a glowing globe is there. It contains Pepsi. Apparently, whatever is in there at the time gets everyone in the area addicted to it. Toadette suggests it was put in there by accident or by experimenting. King Bob-Omb, however, comes into the room and kidnaps Toadette and Toadokay.
Mario, Peach and Police Guy then try to storm in, but King Bob-Omb attempts to capture them. However, Toad, Rievoah, Chain Chomp and Lemmy then come in through the window on a clown vehicle and Chain Chomp knocks him out. They then proceed until they are surrounded by King Bob-Omb. They also notice Toadette and Toadokay in cages.
Rievoah and Toad try to tackle King Bob-Omb, but then they notice Bobbert bombing his way into the castle with Tiarer and Berinda, with King Bob-Omb calling Bobbert a traitor. Lemmy then tries to sneak behind the throne and steal the wand, but gets swallowed by Petey Piranha.
Police Guy frees Toadette and Toadokay, but King Boo gets back up. Berinda then throws a large set of Pepsi cans onto the ground, which catches everyone except Tiarer, Peach and Toad's eyes. Berinda then uses the wand to free the kingdom from King Boo's clutches and the Pepsi curse. Petey Piranha also spits out Lemmy after this.
Princess Peach then gives the group, including Lemmy, an award for helping save the kingdom. Troop Sr. is also glad Rievoah and Berinda stopped the Pepsi habit, though they still like drinking a few cans a day.