Stepbrothers enter a gloomy alternate universe controlled by an evil scientist, who has banned all things related to summer, and battle to restore order to the Tri-State area.


Vincent Martella Phineas Flynn
Thomas Sangster Ferb Fletcher
Ashley Tisdale Candace Flynn
Caroline Rhea Linda Flynn-Fletcher
Richard O'Brien Lawrence Fletcher
Dee Bradley Baker Perry the Platypus
Alyson Stoner Isabella
Jeff 'Swampy' Marsh Major Monogram
Dan Povenmire Dr. Doofenshmirtz
Kelly Hu Stacy