An enemy lurks in the prince's inner circle. He'll do anything to escape justice... even commit murder.

England, 1923. Love is in the air and all eyes are on Windsor Castle, where the royal family is celebrating a new royal engagement.

When party invitations are sent to only an elite few, Dora and Rex's invite comes with strings attached.

There's a traitor hiding within the prince's inner circle. Dora and Rex, England's preeminent undercover spy team, are assigned to uncover the turncoat.

Their sole lead is a tip from an anonymous informant. To get the clue, they must meet him privately during the engagement bash.

But, when they show up at the secret rendezvous, instead of a clue, they find a dead body and Rex's best friend Clark holding the murder weapon.

Has Clark turned traitor or was he framed? Can Dora and Rex work double-time to clear their friend's name and identify the real killer before Scotland Yard's leading investigator puts Clark away for life?