The Boxcar Children are vacationing on an uninhabited South Seas island, but soon suspect that someone else may be there too-- someone who may not want them around!
The Alden children find a hidden cave in the old woodshed, resolve the problems that have plagued the Alden farm and patch up the misunderstanding between Aunt Jane and Andy Bean.
The Boxcar Children, now living with their grandfather, spend the summer on their Aunt Jane's ranch. Their aunt seems quite unhappy until at the end of the summer a surprise discovery brings happiness to all.