Sonic has visited Porker Lewis on the Floating Island. Although the pig is keen to talk about the island's ancient technology, Sonic is more worried about the Kintobor Computer who isn't quite what he used to be (since Grimer hacked into him. Knuckles the Echidna interrupts the conversation, alerting them to the fact that a big invader has broken through the island's forcefield. There's also something small there, but the heroes are more interested in the big threat. Seeing that it is a large Badnik, Sonic and Knuckles jump into the Zoom tube. Porker is left to tidy up "or something", unaware of two familiar shadows lurking behind him...
Sonic and Knuckles emerge and begin to bicker about Sonic wanting to take all the glory. Nevertheless, the pair smash into the Badnik, although the threat remains intact. Sonic leaps into his Vortex Attack, something that usually rips Badniks to pieces. However, the attack fails this time, so Knuckles leaps in to teach him a lesson. Sonic realises that the Badnik is touch defensively, but doesn't seem to do much. The revelation comes to him in an instant and, remembering there was a small object accompanying the Badnik, Sonic rushes back to the Emerald Chamber, leaving Knuckles to fight the robot.
Moments later, Sonic returns to find Porker unconscious in the island's tunnels. Looking into the Emerald Chamber, Sonic spots old foes Grimer and Nack the Weasel. Grimer is ecstatic, having found the exact spot that Doctor Robotnik vanished some weeks sooner. Nack revels in their victory but Grimer is keen to get to work, not wanting Sonic to know that Robotnik is still alive. Unfortunately for him, Sonic has been listening and marches in, wondering how Grimer got out of prison. Nack deals with Sonic, firing a capsule filled with stun gas at him. As Sonic recovers, Grimer and Nack both turn on their transformation belts and begin to shrink. Sonic launches at them but is too late, only managing to knock the bag off Nack's bag. Meanwhile, Grimer and Nack continue to shrink, the weasel noticing his bag has gone. In front of them lies the planet of Shanazar, the probable location of Robotnik, his faithful Grimer's location!
- It is later assumed that Nack had a spare transformation belt in his backpack, allowing Sonic to also shrink and follow them.
- This adventure follows on from Whatever Happened to Grimer?, Secret Enemy and Revenge, stories which followed the criminals and their last moves. It also references the events of Showdown and how Robotnik disappeared.
- The Badnik that Sonic and Knuckles fought had a "V"-shaped crest on its head, similar to Shortfuse the Cybernik and a Roller Badnik.
- Lew Stringer is erroneously credited for the script to this story.