Dark Day in the Deep Sea

The #1 Bestselling chapter book series that has captured young imaginations for over 25 years is back with refreshed covers and an adventure that plunges deep beneath the waves.

When the magic tree house whisks Jack and Annie to a tiny, deserted island surrounded by endless ocean, they wonder how they’ll ever find their way home. But rescue comes in the most unexpected form—a ship full of explorers and scientists on the hunt for something extraordinary: a legendary sea monster lurking in the deep.

As the brother-and-sister duo join this thrilling maritime expedition, they’ll discover that the ocean holds mysteries far beyond what they imagined. From the deck of a research vessel to the darkest depths of the sea, this adventure combines real marine science with the magic and wonder that has made this series a staple on children’s bookshelves everywhere.

Perfect for young readers ready to dive deeper: Formerly numbered as Magic Tree House #39, this book is now part of the Merlin Missions series—designed for kids who’ve mastered beginning chapter books and are hungry for more challenging adventures with their favorite time-traveling pair.

Whether your young reader is already a fan or just discovering Jack and Annie’s world, Dark Day in the Deep Sea delivers the perfect blend of action, learning, and page-turning excitement. It’s the kind of book that turns reluctant readers into enthusiastic ones, one magical adventure at a time.

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