Sonic and the Chaotix continue their quest to make sure Clean Sweep Inc. is totally shut down! A defeated Clutch gave them the info to check out one of his former facilities to confirm for themselves that the only operations still active are the automated systems. They're joined by Shadow and Rouge, who are also investigating Clean Sweep. But is Clutch telling the truth? The data they download from the facility doesn't 100 percent match his story. Rouge plans to look into it further but informs Sonic that Tails isn't the only one whose Chaos Emerald has gone missing recently. Troubled over who could be stealing the Emeralds, Sonic doesn't realize that someone is tracking him. Who could it be and why?! Volume 21 collects issues #79-83 of the Sonic the Hedgehog comic series and the Chasing Shadows one-shot.