Lenny Lemmon is looking forward to Olden Days Day at school. It’s a chance to break the routine and try school as it was years ago.

It explains the blackboard in the corner, his teacher’s bad temper and why his friend Sam looks like Oliver Twist. And Lenny’s pleased with his own contribution, too. It’s in a cardboard box at the back of the class at the moment because it’s not yet time to shine.

Except it escapes and ends up in the bowl of sick, sorry, gruel, that Amelia Kelly has brought up, sorry, in. Soon there are small, gruelly footprints all over the classroom and also a lot of screaming because the rat that Lenny found by the back of the chip shop is FREE. It takes the arrival of cool new girl, Jessica Conrad, to distract everyone.

Jessica has a plan to catch the rat but it’ll cost them. Can the three kids round up the rat before more damage is done? Or will they end up in the headmaster’s office – again. Maybe, but they’re going to need a bigger net…