Struggling lounge singer Johnny Slade lands a gig at a trendy new club, but there’s a twist: he’s required to perform a new, dreadful song every evening. As he performs, he starts to see a pattern—each song coincides with a new crime. Johnny soon discovers that his mysterious patron, who pens these tunes, is actually a notorious mob boss in disguise, using these “Greatest Hits” as a covert method to communicate orders to his gang.