The Sunnydale High Swim Team has become the darling of the school, thanks to its actually winning several meets, putting it one up on the school's other teams. This extends to Principal Snyder encouraging Willow to give a swimmer with an F a better grade and refusing to see Buffy's side of the story when she attacks another swimmer who tries to grope her. To make matters worse, the tow best swimmers have apparently been killed by something that skinned them alive. Suspicion initially falls on Jonathan, a boy who was tormented by the team, but all he did was pee in the pool.
When Gage, the third-best swimmer, is attacked by Angel - who proceeds to spit out gage's blood as if it were battery acid - they suspect steroid enhancement. when Gage transforms into a gill monster, leaving his skin h=behind, the slayerettes realise that none of them died, and it was more than steroids. Xander goes undercover, joining the swim team to get to the bottom of things. In the end, the newly mutated fish-men eat their coach and swim out to sea.