Wyatt Russell is former baseball star "Ray" who has been diagnosed with MS and is now looking for a home for his wife and two children that he can more readily navigate. They alight on a rather run-down property that has a large swimming pool and that's that! In they move and after having had some fairly toxic looking gloop removed from the pipework, discover that it is fed directly from an aquifer and could contain minerals to help his treatment. Boy, does it help! After a few swims his health is improving no end, but his family start to believe that the water is the source of some wickedness...