"The Aldens spend the summer on their aunt's ranch! The ranch is a beautiful place, but it's also the source of trouble between Aunt Jane and Grandfather. As the Boxcar Children explore the land, they make an amazing discovery. Will it help mend Aunt Jane and Grandfather's relationship?"--Publisher's description.

What will the Aldens discover on a vacation to a beautiful island in the South Seas? The island is supposed to be deserted, but as the Aldens explore, they start to find signs that they suggest they are not alone.

"Los hermanos Alden visitan el rancho viejo y venido a menos de su misteriosa tía Jane ... ¡Y pronto hacen un sorprendente duscubrimiento!"--

Henry, Jessie, Benny, and Violet Alden meet Mike Wood and a strange chain of events begins. Mike's house is mysteriously burned down, a man in a blue hat appears, and the Alden's uranium mine is in danger of being sabotaged. The four youngsters must solve the mystery.