In Sonic CD 2, Sonic defeated Metal Sonic and Dr. Eggman in the Death Egg MK III. He saved Amy as he carried her and jumped out of the D.E. Mk III and the egg blew up. In this, Dr. Eggman recreated Metal Tails and somehow the Tails counterpart didn't obey Eggman and went to rule the world on it's own. Sonic showed up 2 minutes later after Eggman called him to come over to his base. Eggman told Sonic what happened. Sonic replied it's Tails's problem, not thier's. Eggman showed Sonic his Time Machine. He told Sonic that at the time when he turned 20 that he gathered the Time Eater's data and made the time machine. It can travel to the past, future, or 2,000 years later. He told Sonic that he needs the 7 Chaos Emeralds in order for the time machine to work. He also verbalized that the emeralds are in each location of Mobius, but he has to watch out for Metal Tails. Sonic sets off to find the emeralds while Eggman looks for the files, when he created Metal Tails, to find more of M.T.'s information and data.