Learning of a secret weapon from the diary of his deceased grandfather, Professor Gerald Robotnik, Eggman infiltrates a high-security G.U.N. facility and revives it using a Chaos Emerald. The weapon – a black hedgehog and self-proclaimed "Ultimate Life Form" named Shadow – offers to help Eggman conquer the world, telling him to rendezvous at an abandoned space colony, ARK, with more Chaos Emeralds. Shadow goes to Central City, encountering G.U.N.'s forces after stealing an Emerald. Shadow has vowed to fulfill a promise to a girl, Maria, which he interprets as one of revenge. Shadow blasts through the military force and meets Sonic. After a brief confrontation, Shadow escapes and G.U.N. captures Sonic, whom they mistake for Shadow.