The day of Sonic's death, Sonic and Tails were with each other until they saperated. Sonic wanted some time to himself and ran to Sunny Valley. Tails began wandering around until he discovered a magical and shiny place (Emerald Paradise Zone). The same day, Sally was busy in Freedom City and had no contact with Sonic.

-Interesting fact:

Excluding the plot, the game is supposed to look like a normal SatAM game project, until an error/ a virus corrupts and takes over it, creating its own levels, destroying the characters and everything else until nothing remains.