Siblings Roger and Dianna Lynton, their cousin Snubby and his dog Looney, invariably get sucked into some kind of adventure, every time they meet.
During their first adventure, they meet Barney (his actual name is Barnabas), who makes an appearance in each of the following books. Though Barney joins the plot much later and it takes a while for the author to weave all the characters as a group. Barney is older than Roger and lives a nomadic lifestyle, working in fairs and circuses. He also has a pet monkey called Miranda, who is quite a match for Loony. So go on a mystery spree with children as they discover the long lost relatives and ..........!!.