Boisterous nightclub entertainer Buzzy Bellew was the witness to a murder committed by gangster Ten Grand Jackson. One night, two of Jackson's thugs kill Buzzy and dump his body in the lake at Prospect Park in Brooklyn. Buzzy comes back as a ghost and summons his bookworm twin, Edwin Dingle, to Prospect Park so that he can help the police nail Jackson. Buzzy and Edwin and identical twins … played by Danny Kaye.
In the end Edwin is on the run and hides in an Opera House … at which time he is able to sing his testimony to the DA ….
On a side note – In 1898 Mum, Dad & I went to Prospect Park in Brooklyn, and there is an almost identical bridge there!!