Gamma was made as one of Eggman's E-Series robots. His first test is to head through Final Egg for shooting practice, then to spar with his "brother" robot, E-101 Beta. Eggman gathers all of the E-series robots and tells them to find Froggy, who has Chaos' tail. Gamma goes to Emerald Coast and finds Froggy. Eggman is pleased with him and sends all the other E-series robots off the ship. He then sends Gamma to get the Flicky from Amy. Gamma goes, but Amy talks to him and tries to be his friend, which overrides his logic circuits and he sets her free.
Eggman calls Gamma to the deck, where he asks him to fight Sonic. They fight, but Amy stops them. Gamma flies away when the ship begins to lose altitude. He decides to save his sibling robots. He heads to Windy Valley, Red Mountain, and Hot Shelter on the stranged Egg Carrier and saves the E-series. When he comes out on to the main deck, E-101 Beta is back, with a more powerful front armor and a vengeance from their previous battle. They fight, and Gamma wins. Beta is destroyed, and the Flicky inside him is set free. E-102 decides at that moment to self-destruct, and the Flicky inside her is set free. Together, they go to find their child, whom Amy Rose has been protecting.