Mystery in the Old Cave by Helen Fuller Orton, 1950.

Andy and Joan Draper are excited about spending the fall and winter in the country. Usually, they live in an apartment in New York City and only go to their family’s vacation home in Vermont during the summer. However, this year, some friends of their father will be moving to New York, and they’ll need a place to stay because they are having trouble finding an apartment of their own. The children’s father has decided to rent their apartment to his friends while his family stays in Vermont. That means that the children will have to go to school in Vermont, but the children like the idea because they will be able to do things that they normally can’t do when the seasons change, like gathering nuts. When the first frosts come, the hickory nuts on the trees fall to the ground, making it easy to collect them.

After Andy and Joan collect nuts for the first time, they decide to store them in the old sugarhouse on the property. Normally, the family doesn’t use the sugarhouse for anything, but it used to be used during the times when their vacation house was a working farm and people tapped the maple trees for their sap to make maple syrup. They would process the sap in the sugarhouse. Sometimes, farm hands also used to sleep there during the harvest.

Soon, the children begin to suspect that there’s a stranger hanging around the property. Their dog, Ponto, barks at someone the children don’t see and comes running back to them, acting like someone kicked him. Later, a strange man approaches them and asks them if they know anything about a cave in the area. Andy and Joan don’t know anything about a cave. The man tells them that it’s supposed to be near the old sugarhouse, but if the children haven’t seen it, it might have caved in or something. He seems very secretive and doesn’t want the children to tell anyone that he’s been asking questions, and the children wonder if he could be the one who kicked their dog earlier. Later, someone (perhaps this strange man) steals many of the nuts that the children gathered and even some cookies. The children change their minds about storing things in the sugarhouse and decide to keep their gathered nuts in an unused room in the main house. The only clue to the identity of who’s been sneaking around is a red pencil that the person dropped.

The children make friends with a boy named Phil who lives nearby. Phil is an orphan who lives with his Cousin John (who he sometimes calls Uncle John because he is so much older), a mean and stingy old man who doesn’t treat him very well and makes him work hard around the house instead of going to play after school with the other kids. He doesn’t even replace Phil’s clothes when they get old and torn. Phil gets a job at the local store to earn some money for a new sweater, but Cousin John even confiscates Phil’s earnings.

Mr. Lane, who owns the local store, is nice, and he tells Andy and Phil about how maple syrup and maple sugar are made, something that everyone in town used to participate in so that it was like a community party. The boys think it sounds like a lot of fun, and while they are talking about the old sugarhouse, Mr. Lane mentions that, once, some thieves joined in when they were making making syrup. Nobody knew they were thieves at first; they were just a couple of strangers who came along with everyone else and started helping out. Later, there were some robberies in the area, and the thieves were found hiding in a cave near the sugarhouse. Mr. Lane says that he and his friends used to play in that cave when they were young, and Andy and Phil decide that they want to find it.

The boys take some tools with them while they’re looking for the cave, in case the entrance has been covered over, which turns out to be the case. Once they dig through the entrance, the rest of the cave appears intact. They find some old bones inside that probably belonged to a bear. They can’t look around much more because the cave is too dark, so they decide that they’ll return later with some lanterns. Mr. Lane tells the boys that there still might be stolen loot around because they never did find everything that the thieves took, including a pearl necklace that belonged to Andy’s grandmother, who was living there back then. Could these things be what the mysterious stranger is looking for?

During the course of the book, Mr. Lane begins to notice that Phil’s cousin isn’t giving him enough food. Cousin John denies Phil food when he refuses to turn over the extra money that he’s been earning to him. Mr. Lane gives Phil food from the store to eat. While Phil is at the store, he overhears the stranger, who calls himself Joe Williams, talking to Mr. Lane. Joe Williams admits that he’s looking for treasure in the area. Mr. Lane says that he doesn’t have high hopes that Joe Williams will find anything around the cave because the whole area was searched thoroughly years ago.

Phil tells Mr. Lane that he can’t stand living with his cousin anymore and wants to run away. Mr. Lane tries to persuade him not to go, saying that he can deal with Phil’s cousin, but Phil has had enough and worries that his cousin will make life hard for anyone who tries to help him. When Phil hides out in the old sugarhouse, he meets up with Joe Williams, who explains to him more about how he knows about the treasure that may be hidden in or around the cave. He’s about ready to give up the search, but Phil finds something that everyone else has overlooked.

In the end, Andy and Joan’s parents decide to take Phil in. Phil’s cousin agrees to sign over custody to the Drapers, provided that he gets to keep the money from Phil’s job that he took and the money that Phil’s mother left for Phil’s upkeep. I’m pretty sure that’s illegal and that the courts and social workers would have something to say about that if this story happened in real life in the 21st century, but in the story, Mr. Draper accepts the deal and basically uses the money that was meant for Phil to pay off his cousin to surrender custody of the boy. The story ends at Thanksgiving, with Phil sitting down to Thanksgiving dinner with his new family, who will really love him and treat him much better than his cousin did.

This is one of those older mystery stories that’s really more adventure than mystery. There’s really only one suspect for the odd person sneaking around, and his reasons for sneaking around turn out to be exactly what he said they were. There is no other hidden purpose or secret past behind that man other than what he said, and in the end, he just kind of leaves the story. The kids don’t have many clues to the location of the stolen items, and in the end, Phil finds them more by accident than anything else.

Sometimes, when I’m unsatisfied by the ending of a story, I like to make up an alternate one of my own. If I were writing this, I’d have had Phil’s nasty cousin be involved in the robbery and the hunt for the hidden loot. For example, maybe he was actually one of the original thieves and had a falling out with his partners, and he’s secretly searching for the rest of the loot they hid for years. Maybe he’s had to redouble his efforts recently because they’re getting out of prison soon, and he wants to get to the hidden loot before they do. Cousin John is money-hungry enough that it could be plausible, and that would allow the story to end with him being sent to prison, which seems fitting.

This isn’t important to the story at all, but I just wanted to say that the copy I have of this book is damaged in a very odd way. On some of the beginning pages, someone has cut out a few of the words, ransom-note style. I don’t know why that happened. There aren’t enough missing for a real ransom note, and some of the cut-out words are still stuck in the pages, but since this is a mystery book, I kind of like the image of someone using it to write some kind of mysterious secret message.

I haven’t been able to find an online copy of this book yet, but Internet Archive has others by the same author.