The woodland at Linbury Court becomes squatters' territory when Jennings comes up with the idea of building huts out of reeds and branches. Jennings and Darbishire are thrilled with their construction, which even includes a patented prefabricated ventilating shaft, a special irrigation drainage canal and a pontoon suspension bridge! The trouble starts when Jennings is put in charge of Elmer, the treasured goldfish, and gets worse when the Headmaster pays the squatters a visit - and if Jennings thinks a game of cricket will be less trouble, he's going to be knocked for six!