Sonic the Hedgehog and Phineas and Ferb: Double Trouble! (The Sequel)

Phineas and the gang go to Mobius to visit Sonic, only to discover that since the year they've seen them everything's changed. The heroes have been driven back, Eggman has powerful allies, and Sonic is missing! Phineas must team up with the surviving Sonic Heroes to defeat Eggman before his new plan goes out of control! Rated for violence and slight language.