Roxton, Malone and Challenger help an Amazon woman attacked by a Raptor. Challenger gets injured and the Amazon tribe repay the adventurer by healing him, but have other things in mind for the men.

Our adventurers end up in a haunted castle with secret passages, cobwebs and all. After some strange circumstances, they feel compelled to re-enact an intriguing murder/mystery which eventually leaves their fate in the hands of Challenger.