Sherlock Holmes is as dashing as ever, but with a little secret: Dr. Watson is the brains behind the operation. When Reginald Kincaid, the actor he has hired to play Holmes becomes insufferable, Watson fires him and tries to go out on his own, but finds that he has done too good a job building Holmes up in the public's mind.
A prince and a fellowship of companions set out to rescue his bride from a fortress of alien invaders who have arrived on their home planet.
Colonel James Damery calls on Holmes when the rich and beautiful Miss Violet Merville announces her engagement to Baron Gruner, a dangerous Austrian. Gruner has persuaded Violet that he is not a killer, and Holmes has to establish the truth and foil the powerful baron.