When the gang learns the location of George Estabrook's hidden Codexes, they must enlist the help of an unlikely ally to retrieve them before anyone else.

Betrayed by one of their own, the gang struggles to understand the meaning behind George Estabrook's map and faces a shocking quid pro quo.

The gang joins Callie at Rosegrave with hopes of saving Frank, but they'll require the help of an old foe and The Power of The Eye.

With Frank back, the race is on to locate the third and final Relic, but the bad guys are hot on the Hardy Boys' trail.

After a shocking blow, the gang must divide and conquer to determine the identity of Deep Voice and get The Core back.

With the help of Drew, the gang makes a daring plan to retrieve The Core, but their loved ones' lives hang in the balance.

The Hardy Boys get what they want most and must race to deactivate The Core before it's too late.

As The Core's true purpose is revealed, the Hardy Boys and their friends must band together to save themselves, and the world, from an unheard-of technology that could forever change life as they know it.