Follows Stephen Lansbury, a London orphan who unexpectedly inherits a remote estate in Cornwall after the death of a distant relative. Upon arriving at Lansbury Hall, Stephen discovers an eerie, seemingly deserted mansion filled with peculiarities: locked rooms, strange sounds, and a pervasive sense of being watched. As he delves into his great-uncle's journals, Stephen uncovers a tale of adventure involving a South American expedition, rare creatures, and a hidden rainforest treasure. Guided by these revelations, he embarks on his own journey to unravel the mysteries of the estate and its enigmatic inhabitants.