Ctrl-Z. A computer like no other. What happens if you push Ctrl-Z? You go back in time… and cause a riot! Alex is used to getting odd birthday presents from Godfather John. But this year’s present is something really weird – a computer that can take you back to an earlier part of the day. That means you can undo all the day’s messes and muddles, right? But as Alex and Callum whiz backwards and forwards in time, they find out what happens when you make mistakes – and when you try to fix them! A brilliantly funny tale of magic and mayhem by Whitbread Award-winning author Andrew Norriss.