The films of the world's greatest detective are spoofed in this mystery-comedy that centers on Sigerson Holmes, the brighter brother of the famed sleuth. The trouble is, Sigerson is terribly jealous of his younger brother and so feels obligated to prove himself superior in every way no matter how inane or picayune. The tale begins as Sherlock and Watson leave the country for a while, leaving Sigerson to investigate the evil doings of his brothers' nemesis Professsor Moriarity, who has absconded with some valuable government papers. He is assisted by a bug-eyed Scotland Yard detective with 'photographic hearing,' and a seductive, enigmatic woman. Merry mayhem and adventure ensues as they try to piece together the clues. It is dangerous work and the hapless elder Holmes nearly loses his life. Fortunately, Sherlock steps in and reveals that he has been there all along, protecting his brother and his friends. The two Holmes then team up to bring Moriarty to justice.