American TV shows never end. Or rather, they end all the time through cancellation, but they’re never meant to end: A successful series will be renewed and extended indefinitely until its ratings finally tank, or it becomes too expensive to produce, or, on rare occasion, its stars and producers have enough clout to demand an endpoint at their discretion. Thus, most popular shows eventually decline in quality, and end up shadows of their former selves by the time they go off the air.

This isn’t the case in a lot of other countries; in Britain, shows are generally designed to last a finite number of episodes, and even successful ones usually only get extended one or two more short seasons. CBS is taking a step toward embracing this concept with its new Harper’s Island (Thursdays, 10 p.m.), a mystery series being promoted as limited to 13 episodes. At the end of the season, the mystery will be solved, all the questions answered, and that will be it.

Admirable as this approach is, it would certainly be more promising if the show itself were better. There are plenty of intriguing serialized dramas that would have benefited greatly from predetermined endpoints—The X-Files, Prison Break, Heroes—but instead kept going long past the point where their concepts became untenable. Harper’s Island, however, doesn’t have the excitement that any of those shows did when they started, and thus the main thing it has going for it is that if you stick around until the end, you’ll learn exactly what’s going on.

What’s going on at the start is a pretty standard murder mystery: On a small island off the coast of Seattle, family and friends gather for the wedding of rich girl Trish (Katie Cassidy) and working-class guy Henry (Christopher Gorham). Seven years before, the island was the site of a killing spree that left six dead (including the murderer). Now someone seems to be picking off the wedding guests one by one.

It’s undeniably hokey, and the pilot doesn’t indicate anything particularly intricate or innovative going on. The show is essentially a cheesy slasher movie divided up into 13 parts, with added soap-opera elements (and less gore, since this is network TV). Red herrings abound in the first episode, which does make figuring out the identity of the killer into a fun guessing game (one of the most obvious suspects is killed off by the end of the hour).

The large cast is full of mostly indistinguishable pretty faces, at least at this point, although there’s time for each to develop a little more personality (and presumably, the cast will get smaller—we’ve been promised a death in each episode). Harry Hamlin is the only real standout, as Henry’s lecherous uncle, but of course there’s no guarantee he’ll stick around (nearly every actor is billed as a “guest star”).

The pilot underwent some rejiggering after the show was announced nearly a year ago, and writer-producer Jeffrey Bell, who’s worked on Alias, The X-Files and Angel, was brought in to run things. So there’s certainly potential for something a little more complex and riveting than the amusing camp on display so far. At this point, Harper’s Island is far more notable for its format than for any of its actual content.