Computer fanatic Robin and twin Helen become chance owners of a mouse (they christen Minimus) with magic properties. They meet Grizelda and Emmeline, friendly witches who teach them how to use his magic. Scilly Isles, Grand Canyon and the Great Exhibition feature in their trips Lord Radleigh, local aristocrat, meets them. He wants a rocking horse. On visiting Pepperton in the1950’s they find one at Bosconi’s workshop. Eustace Thrimp, junk shop owner and “Friday People” member pursues them for Minimus. He tricks Grandma, steals the mouse, visits Bosconi and orders one. The twins manage a return trip and trap him the 1950’s where he’s arrested. His wife and the twins return to the 50’s and rescue him. . He resigns from the “Friday People”.infuriating the leader. Christmas sees everybody happy and the twins at the Hall for lunch. A trip to Lapland is organised using Minimus. Going home in the Rolls-Royce they meet a mysterious stranger who leaves them worried