The mystery comes to a close as the gang finally gets to the bottom of what happened to the original Mystery Incorporated and why they disappeared. The truth, however, is not without its price.
When the gang goes on a quest to find out what happened to the original Mystery Incorporated group, they find themselves trapped in the underground Darrow Mansion.
The gang investigates the curse of Crystal Cove with the help of Professor H.P. Hatecraft. But when a high-tech creature called the Obliteratrix attacks the gang, it's up to them to find out why and how is this related to the curse.
The gang returns from their trip, and find that the whole town has been enslaved by Professor Pericles, Mr. E, Brad, and Judy. So the gang has to save the town, by causing an uprising.