The sea of adventure

When Bill takes Philip, Dinah, Lucy-Ann and Jack on a mysterious trip to the desolate northern isles, everything looks set for an exciting time. But then Bill is kidnapped and the children, marooned far from the mainland, find themselves playing a dangerous game of hide-and-seek with an unknown enemy. Other titles in the Adventure series: "The Island of Adventure", "The Castle of Adventure", "The Valley of Adventure", "The Mountain of Adventure", "The Ship of Adventure", "The Circus of Adventure", and, "The River of Adventure".