Princess Sally calls Sonic to inform him that Knuckles is roaming around the edge of the Great Forest. Sonic, surprised that Knuckles would leave the Floating Island, assumes Knuckles is up to no good. Sally shows Sonic that Knuckles is heading towards Robotropolis. Thinking that Knuckles is trying to cut a deal with Robotnik, Sonic heads off to stop him, Sally shouting at him to try talking it out first as he leaves. Meanwhile, Knuckles arrives at Robotropolis and remembers a conversation he had with Mighty the Armadillo. Knuckles told Mighty how he had seen a Chaos Emerald broken in half not too long ago. Mighty doesn't believe it, but Knuckles tells him that he's certain of it and that he refuses to let it happen again. He says that, since the island was once supported by twelve emerald