19世纪,年幼的福尔摩斯和年幼的华生医生在同一所寄宿学校就读。福尔摩斯在幼年就表现出了非凡的观察和逻辑推理能力,这让他在学校里很受同学注目。他与华生还有他暗恋的姑娘Elizabeth Hardy一起,在一次偶发的自杀案中抽丝剥茧逐渐走入伦敦的黑巷中破获了惊人的罪案。Sherlock Holmes and Dr. Watson meet as boys in an English Boarding school. Holmes is known for his deductive ability even as a youth, amazing his classmates with his abilities. When they discover a plot to murder a series of British business men by an Egyptian cult, they move to stop it.