Dive into an OceanX Adventure! Marena Montoya and her BFF Aisha go on a brand-new ocean adventure using their scientific skills to solve another mysterious puzzle.

Lucas' voice broke the silence. "Remember the lessons you learned on the OceanXplorer. Colin said always prepare for the unexpected..."

I finished the sentence for him. "...and when it happens, don't panic. Just think your way through it."

Science reporter and budding junior detective Marena Montoya comes to the rescue in the next adventure in the OceanX series.

Marena has discovered an important clue about a treasure-laden Spanish galleon lost at sea centuries ago, but has no idea how she could search for the ship until a wild series of events lands her, and her older brother Lucas, straight into the hunt.

Using her newfound skills from her time aboard the OceanXplorer, Marena bravely navigates the perils of deep-sea exploration, and learns the most important lesson of all—that there is more than one type of treasure. 

This page-turning adventure combines the scientific discoveries of the world-renowned OceanX project with an intrepid new heroine who learns the power of speaking up, asking questions, and learning from mistakes.

MEET THE OCEAN EXPLORERS: 5th-grade junior journalist Marena, her BFF Aisha, and Marena’s teenage brother Lucas use critical thinking and sound science to solve exciting ocean mysteries.

MENTORED BY OCEANX: Marena and Aisha are mentored by Dr. Anna Knowles, whose character is inspired by the real-life scientists of the world-renowned OceanX project.

REAL SCIENCE: Each mystery is based on actual oceanic scientific research and discoveries, filled with facts about the ocean world.

MIDDLE-GRADE MILESTONES: Once proud of her curiosity and endless questions, 11-year-old Marena is starting to feel self-conscious about calling attention to herself. With the encouragement of her teacher and mentor, she learns to embrace the qualities that make her special.

COLLECT THE SERIES: Mystery at the Aquarium, Underwater Secret Agent, and Galapagos Island Hitch also available!