The Alden children are staying at the New England farmhouse where their grandfather grew up. There are many stories and legends about the old farm, and there's a woodshed near the house that holds a surprising secret... a secret that dates all the way back to the Revolutionary War!

When the Aldens take a summer trip to the New England coast, they have a fun place to stay: a lighthouse! But strange things happen after it gets dark - an unknown woman is seen walking around, and Watch, the Aldens' dog, wakes up growling late at night. Can the Boxcar Children shed light on a seaside mystery?

While helping fix up the old house their cousins have bought, the Aldens hear stories about its being haunted and find evidence suggesting that there may be a ghost there.

The Aldens are spending spring break on a beach, but they aren't just soaking up the sun. They're protecting an endangered species! Their job is to mark sea turtle nests so the eggs can be moved to a safe place to hatch, but someone is digging up the eggs without permission. Can the Boxcar Children figure out what's going on and help save the sea turtles?