Arsenic & Old Lace is a dark comedy/farce based on the stage play that high schools like to perform and directed Frank Capra. It stars Carey Grant, Raymond Massey, Peter Lorre, Priscilla Lane, Josephine Hull, Jean Adair, and John Alexander.
Mortimer Brewster (Grant), a well-known writer and critic, is about to get married to his girlfriend (Lane). This is, in the movie, presented as a big deal because he's a well-known detractor of marriage in general, but that subplot was apparently added for the film and never really goes anywhere. Anyway, he goes home to tell his two spinster aunts, Abby (Hull) and Martha (Adair) the good news - but then he learns their little secret.
His aunts, who rent rooms in their enormous house, have many charitable endeavors. One of them is poisoning solitary old men who come to stay with them and burying them in the basement, with the help of their youngest nephew, Teddy (Alexander), who is firmly convinced he's Teddy Roosevelt. Mortimer, upon finding the body of their latest victim, flips out and tries to shift the blame to Teddy, knowing he can pull strings and get him committed to a sanitarium, but that takes some doing and he also tries to keep all this from Girlfriend (sorry, her name is actually Elaine, but she doesn't have a lot to do in this movie except get shoved around).
Further complicating the issue: Mortimer's evil older brother, Jonathan (Massey, filling in for Boris Karloff, who played the role onstage but was too busy doing so to be in the movie, which is a bit of a mindfuck) arrives with his accomplice/plastic surgeon Dr. Einstein (Lorre) in tow, looking for a place to hide out. And then all hell kinda breaks loose, in the manner of farce, and we end up with Teddy and the aunts going to the sanitarium, Jonathan being arrested, Dr. Einstein sneaking out the door, and Mortimer and Elaine smooching.
So, I haven't actually seen the stage play (only scenes in acting classes), so other than the weird "I hate marriage but am getting married" subplot for Mortimer, I'm not sure what changed. That said, I think this is pretty funny and light for a movie about murder; it drags a little in the final act, IMO, because it's a movie, and not a play, and I think the way to avoid that would have been to cut the stuff in the beginning where Mortimer and Elaine are getting a marriage license. But in the moment, everything is very snappy. Alexander and Lorre, in particular, are perfect in their roles, Massey channels Karloff appropriately, and Grant, while he apparently hated this performance for being too over the top, works nicely carrying the load of reacting to all the craziness around him.
My Grade: A-
Rewatch value: Medium
Next up: The Long Kiss Goodnight