Members of the Springhill Farm Gang(SFG) design and build a new version of their raft to float on Bunkers pond. Meanwhile Percy Fieldmouse is pining for his new girlfriend Cornelia who has been kidnapped by the Rat Brothers. Percy's family hatch a plan to rescue her from the Rats and march to Bunkers to find the SFG camping with their Jack Russell dog, Jock. Percy's family together with Cornelia's family raid the Rat Den, creating confusion and chaos, which makes the rat brothers chase the mice who lead them into the jaws of Jock. Once the rescue is completed by the mice, the SFG finish their raft and successfully sail it on the Bunkers pond. At the end of the day, the farmer, Mr Lawrie comes in his truck to take them home, but before they leave he has a go on the raft himself, with hilarious consequences.