Too many great shows end their runs on a bad note. But the AMC drama won't be one of them.

AMC

If you were to trace the creative arc of most television shows, you would probably end up with a shape that looks more or less like a bell curve. A show finds its voice, rises to a narrative apex, and then begins its (sometimes steep) decline. It's part of the natural life cycle of a long-running series—beholden to breakneck production schedules and the voracious demands of audience attention spans, idea wells start to run dry, plotlines meander and characters stagnate. Even great shows will go through fallow periods, often ending their runs with something closer to a whimper than a bang. But as the fifth and final season Breaking Bad (which will air in two parts between now and 2013) launches on Sunday, it seems poised to become a television rarity: a show that will end at the height of its power.

Some of the best and most thrilling serial dramas of the current television era have tripped as they neared the finish line. Count me among fans who thought that the famously ambiguous ending to The Sopranos—the show that gave rise to the contemporary television antihero--failed to deliver adequate closure to a series that had been as much about heart-stopping drama as the existential malaise of a modern criminal. Lost spent its last seasons wandering aimlessly through a purgatory of smoke monsters and metaphysicalgobbledygook. The Syfy reboot of Battlestar Galactica painstakingly built up complicated mythologies about dreams, symbols, and the mysterious origins of the Cylon race, but left some of its central questions only vaguely addressed by illogical timelines and angel-like apparitions. (If Breaking Bad ever releases a promo image showing the characters arranged around a table Last Supper-style, it could be a sign that we're headed for trouble).

Not all series follow this trajectory. The Wire gets my vote for the most consistently excellent drama of the last decade, maybe ever, although even that show's final season fell slightly short of previous installments. Friday Night Lights declined steeply in its second season, only to build itself back up and end on a graceful, emotionally authentic note. While it may be natural for shows to flag at various points in their runs, it's a deeply disappointing experience for viewers when a series loses creative juice just as the writers need to muster all their powers to provide an expected spectacular conclusion. In a New York Times Magazine article, Heather Havrilesky argued that serial dramas that depend on sustained suspense and mysteries layered on mysteries—or, more specifically, Lost—are killing the current golden age of television by making it up as they go along, and failing to satisfactorily solve their Rubik's Cube plots by series end.