Believing that over-civilization was destroying the race, Eli Tapper, an eccentric millionaire, took two unrelated orphan children, a boy and a girl, and placed them in a wilderness, there in the care of an old tutor, David Winters, to grow up as a new Adam and Eve, and become path-breakers of a better race.

When a couple of scammers hold young Alice Faulkner against her will to discover the whereabouts of letters whose dissemination could cause a scandal affecting the royal family, Sherlock Holmes decides to take over the case. (Considered lost, a copy was found in 2014, in the vaults of the Cinémathèque Française.)