Currently Watching - Song of the Thin Man (1947)

And finally the last of the Thin Man movies...

A charity benefit sponsored by David Thayer is staged aboard the S.S. Fortune, Phil Brant's gambling ship. The entertainment is provided by a jazz band led by Tommy Drake and featuring singer Fran Page and talented but unstable clarinetist Buddy Hollis.
After a set, Drake informs a displeased Brant that he is quitting, having gotten a much better booking through Mitchell Talbin. However, Drake has a problem; he owes gangster Al Amboy $12,000. When Amboy (who is at the party) hears the news, he demands full payment that very night. Drake begs Talbin to give him an advance, but Talbin is unwilling to part with such a large sum. In desperation, Drake sneaks into Brant's office and opens the safe. However, he is shot from behind and killed.
Brant and socialite Janet Thayer elope, since her father David disapproves of Brant's lower class background. The next morning, they show up at Nick and Nora Charles's apartment, having learned that Brant is the prime suspect in the murder. When a bullet narrowly misses Brant, Nick turns him in to the police, having decided it is safer for all concerned. Then Nick starts investigating.
Sneaking aboard the Fortune, Nick discovers on the back side of a sheet of music a receipt signed by Amboy acknowledging that Drake's debt had been paid. Nick then runs into Drake's band, allowed back on board to collect their instruments. When he questions them, he learns that the bandleader had many enemies, among them Buddy Hollis. Musician Clarence "Clinker" Krause agrees to help Nick track Buddy down, but they have no luck.

Nick and Nora visit a hostile Janet. The bullet that killed Drake likely came from an antique gun, and Nick knows Janet's father is an avid collector. Sure enough, he finds one gun missing from Mr. Thayer's collection. Janet leaves after getting a telephone call. Nick and Nora follow her to Fran's apartment. There they find Fran's body; she was stabbed in the back very recently. Janet claims Fran called to sell her some information, but that she got there after Fran was killed.
Nick finds a matchbook from a hotel in Poughkeepsie. That eventually leads him to a rest home where Buddy is undergoing treatment. The musician is too badly shaken up to answer Nick's questions, though Nora's presence seems to calm him down. When Nora sneaks back later by herself, Buddy becomes agitated, confesses to the murder, pulls out a gun, and tries to shoot Nora. Fortunately, he misses. Nick does not believe the deranged man's confession; Drake was slain by a well-aimed shot.
Nick decides to gather all the suspects together by arranging a party on the reopened Fortune and announcing that Buddy has fully recovered and will reveal the real murderer's identity that night. It is Nora who notices the vital clue. Amboy's wife shows up wearing a valuable necklace that matches the earrings of Mitchell Talbin's wife Phyllis. Sometime later, the necklace mysteriously reappears on Phyllis's neck. When Nick confronts Mitchell, Phyllis reveals that it was she who paid off her lover Drake's debt using the necklace. As Nick prompts Buddy to finger the killer, Mitchell finally confesses to both killings and pulls out a gun. An enraged Phyllis shoots him first, but her husband is only wounded. Then, despite Nick's pleas, she fires again and again, finishing the job.