Introduction

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.

Adventures

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 the 1950s they find one at Bosconi's workshop.

Conflict

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 in the 1950s where he's arrested. His wife and the twins return to the 50s and rescue him. He resigns from the Friday People, infuriating the leader.

Conclusion

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.