Lily and Robert Brewster are orphaned siblings, now in their twenties, living in their late great-uncle's mansion, Grace & Favor, with Mr. & Mrs. Prinney (the executor of their uncle's estate and his wife), a maid, and a couple of borders. It's 1933, the Great Depression is in full swing, and Franklin Roosevelt has just been sworn in as president.
In fact, Robert is away watching the Inaugural in Washington while Lily, at home in Voorburg, NY, a little town on the Hudson River, was visiting Miss Twibell, an experienced nurse who has turned her family home into a nursing home. She's down one experienced nurse who is out sick, and her bunions have flared up, limiting her own ability to take on the work. She wants to hire Lily and Robert to help out until the nurse can return. They live in a mansion, but are broke like everyone else, and Lily and Robert are happy to take the temporary work.
They haven't been working there long one one of the most difficult patients, Sean Connor, is found dead in his bed during his wife's visit, and is discovered to have been suffocated with his pillow. But who would bother to kill a man who had at most another day to live?
Chief of Police Howard Walker is quickly on the case, but Lily and Robert can't contain their curiosity about what happened. Meanwhile, the chief of police in a neighboring town has an unexpected and unidentified dead body fished out of an especially nasty local lake, and, being limited by a flare-up of gout, and having little confidence in his inexperienced new deputy, asks for Howard's help.
This is a very light, pleasant cozy, having no depth at all and aspiring to none. Lily and Robert are likable young people, raised in wealth and comfort, but completely at ease with taking on whatever jobs they can find to help earn their keep. There's not much history here, but what there is, is accurate. That's beside the point, though, really. This is light entertainment, with the historical setting meaning the characters don't have modern tools to help them solve the mystery.