Today Bob and the team have a very exciting job to do. They are building a bridge over the river to where Mr Sabatini's new bakery will be. Bob promises Scrambler that he can be the first machine across the bridge. Wendy will be working on the opposite bank and its Scrambler's job to take her the bags of concrete she needs. Dizzy is also needed to mix the cement, but the others stay behind to start forming the base. Desperate to get the job done as fast as possible, Scrambler rushes off - while Dizzy struggles to keep up, skidding off the path and into the marsh losing her Talkie-Talkie! Wendy sends Scrambler back to look for Dizzy. He finds her stuck but is reluctant to fetch Bob as this will slow down the finishing of the bridge. Scrambler decides to go back to Wendy, grab some rope and pull Dizzy out himself. Meanwhile Bob, Muck, Roley and Lofty are waiting for the concrete to finish the job. Bob and Lofty decide to look for the two missing machines.