Shadow notices Eggman accessing Professor Genald Robotnik's files and suspects he's up to something. Shadow then informs Sonic about a possible new evil scheme as he's reporting to G.U.N. Naturally, Sonic goes to Eggman's lair to stop whatever he's planning. Sonic ends up interrupting Eggman during an experiment which results in an explosion. Everyone seems to be okay, but the explosion caused a mutation in the RNA-DNA transcription process in Sonic.