Nick Charles (William Powell) and his wife Nora (Myrna Loy) are caught up in the investigation of the death of a prominent band leader on a boat in New York City Harbor. But the case soon leads them into the world of be bop jazz and late night jazz clubs, which requires the assistance of musician Clarence 'Clinker' Krause (Keenan Wynn) to guide them through. This guides them into the sanitarium where Tommy Edlon Drake (Phillip Reed), another jazz musician, has been institutionalized after having a nervous breakdown.