Description: Rod, Brains, and Tucker use technology from Kai's time to clean up the river and town dump. Mr. Shephard is Scoutmaster. They drop Dion off in Sparta 450 BC, which is interesting, because previously he seemed to relocate permanently to their time period, living in the hills. In an earlier story it didn't seem like he had a home in Sparta anymore. Their town formerly called "Watertown" in 1970 if now called "Waterton" - it lost a w! It's mentioned that the water treatment process is put into use elsewhere, which may be the first real instance of paradox in these stories --- future technology changes the present, and by Kai's time, it's already known, so nobody really ever invented it.