Frank and Joe exchange truths with their Grandmother and find a long-hidden secret in her home. Fenton finds what he's looking for. Meanwhile, other forces work against them all.

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?