Taking a step farther than their mother did and learning the nature of the object at the heart of the mystery, Frank and Joe's unity fractures over what to do next. Tensions between Chet, Callie, Frank and Stacy reach a peak.

Regaining possession of something long-lost, Gloria reasserts old power. Fenton returns and is stunned to see his sons in the middle of secrets that he, too, has uncovered. Frank enters an uneasy alliance, and climactic events are set in motion.

The Hardy boys and the gang embark on a daring mission to finally uncover the truth… but in revealing the truth could they unleash a dark power beyond their control?