Title: The Llewellyn Jewel Mystery
Description: When the Brown children set out alone for a holiday in Wales the biggest adventure they look forward to is climbing the Welsh hills, which could certainly be exciting enough, but little do they dream of uncovering - not to mention solving - the mystery of the Llewellyn jewels.

But for the ugliness of Tabitha, David's pet cat, they might never have become involved in the mystery at all; and her escape from her basket at Plyn-y-Fawr station is the first link in a chain of curious circumstances which leads the children into the most alarming and exciting adventures. The last people they expect to meet in Wales are a gang of crooks, but, happily, "The Brown Detective Agency" is equal to almost any situation.

J. Jefferson Farjeon is a familiar name to readers of adult detective fiction and now he has written a mystery story specially for children which has the plot and all the thrills of his well-known, grown-up books.