Belshazzar's snatched cheese butty

Frog's received the first parcel of Reading Mission goodies for the summer holiday Reading Challenge. He's especialy pleased to get to play with the secret message pens (the writing is invisble until you rub it with the other end of the pen). The sensible grown-ups amongst us wonder if the ink in the pens will last out to the end of term.

"I'll be able to write rude things on the walls," says Frog.

"I think the writing's been on the walls here for a while now," replies Noreen.