After Bowser and Eggman cover London in colored fog and after the imposters attack Toad, Mario & Luigi help Toad get up. Toad tells the brothers about the Imposters. Mario & Luigi meet up with the Imposter Sonic & Tails who challenge the brothers to a battle.
After the Brothers defeat the Imposters, the Imposter disappear as the trio venture on. They run into Dry Bowser & Dry Bones who are guarding the Fog Machine. Dry Bowser & Dry Bones challenge the brothers to an event match.
After they are defeated, Chao finds the Fog Machine which the brothers destroy forcing Dry Bowser and Dry Bones to flee. Toad and Chao thank Mario and Luigi and tell them about Hyde Park where Princess Peach is.