Lily and Mouse are making a special picture on Lily's computer to send to a friend. Then one day, the picture suddenly goes missing while Lily is out. Mouse has got to get it back before Lily misses it! Maybe his friends in the Letter School, Picture Playground, or in the Maths House can help? But when Cursor tells him there's a Bad Bug on the loose, Mouse knows he's got to be double quick. Particularly since the Bad Bug is hungry for important information...Suddenly, Mouse hears a grumble and catches a whiff of someone who hasn't brushed their teeth in ages - the Bad Bug! Luckily, Mouse keeps him at bay with clever language (and cheese) until he manages to rescue Lily's picture out of the recycle bin.