The biggest shake-up in Sonic history starts here! A mysterious illness has attacked Knothole and not even Sonic is fast enough to stop it. But is the illness real? Have the people been poisoned by one of their own, or worse, deceived? The mind-boggling events may even lead to Sonic losing Sally forever!
Antoine carries out his plan to take the throne of Acorn from King Maximillian. Tails spots Sonic. who is with Fiona. Tails asks why Sonic is dating Fiona. Tails explains to Fiona that he was in love with Auto-Fiona, but Fiona points out that she is 16 now and Tails is 11. Fiona would rather date boys that are her own age like Sonic. Tails becomes upset, yells "I hate you!" to Sonic and runs away crying.
Meanwhile, Antoine is taking King Acorn and Queen Alicia back to Knothole to get King Acorn some care with the royal doctor. King Acorn is becoming extremely sick, just like General D'Coolette. King Acorn in his royal chambers is looked after by Antoine, who neglects giving King Acorn the medical attention he really needs. Because of King Acorn's illness, Alicia calls Sally that the citizens need a new King and Queen and Sally is forced to marry Antoine.
Sonic playing his guitar in his room is greeted by Bernadette who brings in Bunnie upset. Both Bunnie and Sonic are shocked that Sally and Antoine are being married. Sonic runs to Castle Acorn to talk to Sally, but he is stopped and humiliated by Antoine. By not giving the King his medication, Antoine has forced King Acorn to go into a coma. Sally listens to Antoine and decides to face her destiny. Sonic decides not to crash the wedding and instead goes to the one person who can talk her out of being with Antoine. Sally and Antoine at the wedding take their vows, of which Sally says "I do"...
In celebration for all she's done for the Freedom Fighters, Sally has organized a party for Dulcy. Upset by the fact she needs to blow the wood with her fire breath, Dulcy flies away. In her thoughts Dulcy had found some dragons that hadn't been roboticized and she lived among them peacefully. When she joined the Freedom Fighters with Sonic and Sally, she was discovered by the other dragons and had her black fire nose ring removed and replaced by a gold one, which did not allow her to breath fire. Dulcy decides to fly back to the other dragons and prove her worth as a dragon, but is attacked by the roboticized dragons.