Greendale is holding a pet show for all the children. Everyone except Sarah Gilbertson has a pet to bring, until Julian "lends" her Jess. However, he goes missing and Sarah and the others try and find him. Jess is eventually found and wins a special prize for helping many people that day.

A group of lost field mice are causing lots of trouble in the Greendale, eating away at Pat's letters, Sara's muffins, Ajay's whistle rope and Nikhil's blanket. Luckily with the help of Pat's penny whistle and Julian and Meera's recorders, the mice are able to be led home safely.