In this third book in the series, readers will join Syd, her furry sidekick Goose, and her father as they are off on a mission to determine if vaccinated bat colonies are merging in a cave in the mountains of West Virginia. After learning spelunking skills to assist them on this exploration, father and daughter set off in the cave before sunlight! After crunching over bones and crawling through a tight pinch, equipment failure leaves them in the dark. The farther they go into the cave, the less likely it seems that the bats, who are suffering from White Nose Syndrome, have a chance at survival. Syd's lapse in judgment finds her falling in the cave, but it's Dr. Gardner that gets injured. Syd must go out alone to find help. Thankfully, Goose was not with the pair but waiting for their return. When Syd can't find her way out, it's up to Goose to rescue her family that is Lost in Bone Cave.

In addition to introducing mechanical equipment and skills needed for spelunking, the story serves as a reminder of our impact on the environment and how we can be more considerate stewards of our surroundings. Vandalism is seen, and Syd is conscientious about the glow sticks she has left on the cave floor that could be littering. Readers are introduced to a caving map legend, various cave features, cave formations, and STREAM (reading added) challenge at the end.