The movie centers on Danny Kaye playing “Dingle,” a nightclub performer who’s charming but occasionally grating. After seeing someone get killed, he becomes embroiled with dangerous criminals. Following his death, his spirit reappears to encourage his shy twin brother to assist the police in bringing those responsible to justice. The storyline involving two personalities creates chances for humorous moments. "Dingle" has to navigate a romantic situation involving his fiancée, “Midge” (Vera-Allen), who is also engaged to the deceased man, and “Ellen” (Virginia Mayo), a quiet librarian drawn to his more reserved side. This love triangle feels tiresome and resolves in a fairly expected manner; truthfully, the narrative itself isn’t particularly memorable. Kaye shines most when portraying his twin under some kind of influence—the "Otchi Tchorniya" flower-allergy sequence stands out as a high point. The special effects are also worth noting, with both versions of “Dingle” appearing together in scenes at times, and the ghostly figure even passing through solid objects. Those who already like Danny Kaye might appreciate this film more, but I felt his performance overshadowed everything else; the rest of the movie seems to exist solely to showcase him, and most of the songs are disappointing, with the exception of Leo Robin & David Rose’s “So in Love.” It's unusual, vibrant, and moves along well, so it should appeal to some viewers—it simply went too far for my taste.

Source on TMDB