Johnnie (Bert Wheeler) is a would-be songwriter; Newton (Robert Woolsey) is a would-be inventor. Both work at a cigar stand in the lobby of an office building. Johnnie wants to sell a song to Winfield Lake, a song publisher who also owns the building. Lake's secretary, Mary (Betty Grable), is Johnnie's sweetheart. When Lake turns up dead, circumstances conspire to make Mary and Newton think that Johnnie is the killer. They conspire again to implicate Mary, who goes to jail. But who really shot Lake? Who is the Black Widow, the blackmailer who had threatened him? The other characters in this wacky murder mystery are: Lake's suspicious wife, a self-satisfied private detective, a seemingly slow-witted janitor (Willie Best), Lake's auditor, a songwriter who thinks Lake is stealing from him and another who thinks everyone is stealing from him. It's up to Newton and his truth machine to reveal the real killer.<br /><br />The baby-voiced Wheeler and the cigar-chomping Woolsey strike me as an arbitrary pairing, but they made several movies together in the 30s and some of them were funny.<br /><br />Not this one. George Stevens, who went on to have a distinguished career, directed this dismal comedy with a tedious murder mystery plot. But two scenes are good, and both feature Wheeler and Betty Grable singing the excellent "Music in My Heart," written by Dorothy Fields and Jimmy McHugh. The first time, they sing it walking up a staircase (after which they dance back down). Later, Wheeler and Woolsey are on stilts so that they can see and talk to Mary, who is in a jail cell on a high floor. Wheeler and Grable sing to each other through the bars.<br /><br />"The Nitwits" has a few laughs, but the level of comedy is best illustrated by Woolsey's line: "Sonny, you've got the brain of a six-year-old boy. And I'll bet even he was glad to get rid of it." It's watered-down Grouchowho didn't use the superfluous "even" when he said it.