Replying...
Intro. After what happened in Sonic 3 (the confrontation with Shadow, against Gerald Robotnik and that in the end Shadow would help him stop the eclipse cannon). And see how Eggman and Shadow sacrificed their lives to save the planet from the eclipse canyon. Sonic returned home along with Knuckles, Tails, Maddie, and his father Tom, in the process of recovering. But it would be in for a big surprise just a month after what happened with the eclipse cannon.

Sonic Movie (Sonadow)

@Shaina