Only Team Venture knows how to put the very real, life-threatening element of danger back into Halloween.

A three-month period in the lives of our heroes and villains is chronicled. Dr. Venture recruits college interns to help him complete a project for J.J. in time, but things go awry. Dean makes a life-changing decision after Triana rejects him, and Billy Quizboy acquires a new archenemy.

The Ventures travel into the jungles of Central America to find an invention that has developed a mind of its own.

While the Monarch and his wife attempt to destroy the Venture compound once and for all, the Monarch learns a startling secret about his past. Meanwhile, Twenty-One tries to create a new SPHINX... and inadvertently recruits the members of the old SPHINX.

A figure from Dr. Venture's past haunts him during his annual vacation to Spanikos.

OSI has a riot on their hands when the super-villains in their custody make a desperate bid to escape.

Dean pays a visit to the mystery woman in his life, while Hank and Dermott play a prank on Dr. Venture which leads him on a quest to find his mystery friend and rescue him.

Brock goes undercover to rescue a volunteer undercover operative helping the OSI track down the Council of 13, and ends up in a night club...

When Rusty is apparently killed by the Monarch, Hatred sends the boys off to live with their godparents, and then turns to Twenty-One for help to infiltrate the Flying Cocoon and recover Rusty's body.