Angela and Old Tom go to the local swimming pool, where they meet Lucy who is practising for her swimming certificate. Billy is also there and starts showing off. However, he goes too far and is kicked out of the pool by the lifeguard. Angry and jealous, Billy tries to sabotage Lucy's attempt at her swimming certificate by turning on the pool's wave machine. However, he accidentally breaks the machine, knocks out the lifeguard, and ends up in the pool himself. Old Tom saves them both by ingeniously pulling out the plug and draining the pool.