Anne, Julian and Dick are going on holiday and for the first time they are going to visit their Aunt Fanny, Uncle Quentin and their tomboy cousin Georgina (or George) at Kirrin Cottage. But Uncle Quentin is busy working on a secret project. However a stranger by the name of Mr. Curton shows up and seems a little too interested in Uncle Quentin's project. Then, when Uncle Quentin goes missing, George must get together with her cousins in an attempt to try and save her father.
—Darren Harrison