To save the kingdom, Princess Sally must sacrifice her feelings and do what must be done... go along with an arranged marriage! Can her one-time love, Sonic, race to save the day before Sally walks down the aisle? Is Sonic fast enough to stop the mysterious trader from destroying the Kingdom, or will a new king mean the end of the kingdom?
Antoine married to Sally plans to kill the king in order for him to be placed onto the throne. Meanwhile Sonic didn't have any success persuading Knuckles to stop Sally from being with Antoine. Sonic runs back to Knothole and crashes the after wedding party, which he wasn't invited to by Antoine. Sonic is taken away by the Royal Guards and arrested by Antoine, Sally not being able to help Sonic wanting to be loyal to her husband.
Elias Acorn returns to free Sonic from his prison, Elias believes that Antoine married Sally in order to elevate himself to the throne and Sonic doesn't believe that Antoine could pull something off. Finding King Acorn with Antoine, Elias stops Antoine from killing him, but they don't notice his needle. Antoine plans to kill Elias before the King, and shows Elias and Sonic to the Queen and Sally. Sally and Alicia Acorn ready to begin the coronation are stopped by Elias who claims the right to the throne, seeing he is the first-born to stop Antoine. Sally happy that Elias is king, Antoine ready to congratulate Elias with a handshake is stopped by Sonic. Sonic notices the needle in his hand that he was about to kill Elias. Sonic reveals Antoine as Evil Antoine putting that Antoine was never a fighter, lacked killer instinct and not even Bunnie could prove how he got the scar. Sonic uses Evil Rotor's zone-link generator to teleport to Antoine in Anti-Mobius and taking him back home, dumping Evil Antoine in his own world.
Elias gives Sally her annulment that allows her to spend the rest of her life to whoever he wants. Sonic reunites Bunnie with Antoine, Bunnie being head-over-heels for him. Sally watching from above surprised Bunnie took him back quickly watches as Sonic goes off with Fiona, Tails crying at the scene.
Dulcy watching the robot dragons roboticizing the other dragons, Dulcy rescues a young dragon named Sparky. The elder dragon noticing Dulcy thinking she led the invasion orders her to be chained up. Dulcy begging that she can help out is knocked by a dead robot dragon. The robot dragon knocked out her gold ring and her fire breath has returned with her being released. Dulcy turns around the battle and the other dragons successfully melt the dragons in lava. Dulcy upset that the dragons were once alive is told by the elder dragon that the dragon's spirit is eternal and someday the dragon's will return. In celebration for what she did, the elder dragon and Sparky give Dulcy back her black ring, which allows her to use her fire breath once again.