There's an interesting theme at the core of this episode: that schools, particularly American schools, treat their more athletically adept pupils differently in order to bolster the school's reputation. There's probably less competition between UK schools, and certainly less pressure on them to better their rivals, but the point is well made.

We see several examples of how the swimming team works to a different set of standards: members playing solitaire - solitaire??! - in Willow's computer lesson, bullying fellow students, and even Cameron attempting to rape Buffy, all of which are virtually ignored to make sure the school's success at sports isn't jeopardised.

We also get to see exactly how far the team members themselves will go in order to win. It's not surprising that Cordelia has some sympathies with this Nietzsche-like system: "Certain people are entitled to special privileges.They're called winners, that's the way the world works".

All of this would be a little too prosaic to sit comfortably with the series' format, if it wasn't for the fantastical elements, which add interest, and give the episode a modicum of much-needed levity. There are few laughs: Cordelia's rambling speech to Sean, who she mistakes for Xander, is a rare moment of deft humour. It doesn't really sparkle, but Charisma Carpenter delivers it beautifully. p> The sea creatures are atypically unimpressive when you see them in close-ups, but they do look pretty svelte underwater. Traditionally similar stories involve situations where humans are invading the domain of the sea creature, and where they are literally out of their element. This episode rarely mines the potential of such situations, and is nowhere near as suspenseful as, for example, the scene in Aliens where a child is standing in a pool from which an alien could appear any moment.