Ch. 1- After Captain Syrup steals the Bottomless Coin Sack ( see Wario Land: Shake It) Wario and Waluigi chase her down. Syrup seems to have outran them, but Koga dashes out of nowhere and rams into Syrup. As Syrup lands Wario does a Shoulder Barge and knocks Syrup into a wall, and catches the Bottomles Coin Sack. Koga then introduces himself to the Wario Bros., and Wario grabs him and starts hugging him for helping Wario retrieve the Coin Sack. Meanwhile, Koga is telling them about the Frade Bros. and the massive amounts of treasure they've stolen, and how it was Syrup's fault for releasing them. Wario, concerned only with the treasure, grabs Koga and Syrup and rushes off into Shell City with Waluigi trailing behind.
Ch. 2- When Wario, Waluigi, Koga, and Syrup run out of Shell City, Wario smashes into the Archthief Garroozis, who orders them to surrender all of their coins. Waluigi says "what if we don't", and Garroozis proceeds to attack. After beating Garroozis the Wario Bros. take all of his coins (450 coins) and Koga asks him to tell them about Frade and Dimentio. Garroozis refuses and is burned to a crisp by Koga.