Sunnydale High celebrates at the beach after the swim team wins their latest meet.
Buffy and Cameron, a boy on the swim team, connect while watching the waves. Buffy stops the team picking on Jonathan, but he rebuffs her.
Dodd, the captain on the team, goes missing, but his skin is left on the beach.
Willow is running the computer lab class. A student, Gage, goofs off in class and doesn't pay attention. Principal Snyder encourages Willow to pass him to protect the team.
Cameron drives Buffy to school and tries to force himself on her. She breaks his nose in self-defense. Principal Snyder and the coach don't believe her claims; they blame it on her.
The Scoobies do some investigating to find out what killed Dodd on the beach.
Cameron takes a steam and is forced out by the coach. He heads into the cafeteria as he smells something weird. Xander hears a scream, walks inside and finds the Gill Monster.
Cordelia does a sketch of the Gill Monster. Buffy and Willow think someone is targeting the swim team members; Gage is the potential next target.
Buffy patrols and watches over Gage. Willow interrogates Jonathan.
Buffy follows Gage to The Bronze and saves his life. Angelus spits out his blood and doesn't want to feed on him.
Xander goes undercover and joins the swim team.
After the training session, Gage starts screaming in the locker room. He rips off his skin to reveal the Gill Monster. The coach saves Buffy in time.
Willow hacks into the records and finds out the missing boys had symptoms of steroids.
Buffy and Giles goes searching in the sewers. A member on the swim team, Shawn, tells Xander the steroids are in the steam in the steam room.
Coach Marin throws the nurse into the sewer to be killed by the Gill Monsters.
The Scoobies split up to do some investigating. Buffy interrogates Coach Marin and he pulls a gun on her. He makes her jump into the sewer with the Gill Monsters.
Cordelia and Xander go looking for Shawn. A Gill Monster jumps into the pool and Cordelia thinks it's Xander. She makes peace with it, but it turns out to be Shawn instead.
Buffy fights the Gill Monsters. Xander saves her in time, but the coach falls into the sewers. The Gill Monsters kill Coach Marin.
The Gill Monsters go missing and Animal Control can't find them. Xander, and the other members of the swim team, have to do plasma transfusions to reverse the steroids.
The Gill Monsters retreat to the ocean.