Set sail for a spectacular ocean voyage. The Bobbsey family is trading the snowy north for the bright sunshine of Florida and the Caribbean. Boarding a massive steamship, Bert, Nan, Flossie, and Freddie are beyond excited to travel across the sparkling ocean. They spend their days watching playful dolphins, exploring the historic Spanish forts of St. Augustine, and marveling at the incredible sea life swimming just below the deck. But the relaxing vacation takes a sharp and thrilling turn when the siblings discover a mysterious message hidden inside a floating bottle. At the same time, they learn that a friend of their cousin has vanished on a remote tropical island. The brave children immediately switch into detective mode, determined to uncover the truth behind the disappearance. Join the young adventurers as they navigate fierce ocean storms, search hidden island coves, and even cross paths with a dangerous band of modern-day pirates. You will hold your breath as the twins piece together the watery clues to rescue the missing sailor. This classic maritime mystery blends beautiful tropical settings with high-stakes action, proving that the deep blue sea is full of incredible secrets.