Even fans who drifted away from the final seasons of “” probably have some residual affection for the improbable series. The first season paired its unusual premise — a brother breaks his sibling and a gang of misfit inmates out of jail, in part thanks to an elaborate plan tattooed on his body — with a well-chosen cast that knew how to make the best of the show’s pulpy, action-oriented foundations. Dominic Purcell and Wentworth Miller grounded the brothers they played in effective ways, no matter how gonzo the circumstances they were in, and stars Robert Knepper, Paul Adelstein and Sarah Wayne Callies added lively and credible supporting performances to the melodramatic adventure yarn.

So it’s puzzling that the return of “Prison Break” takes so little advantage of all that potential, and offers up a incarceration saga that is by turns mechanical, grim and overly convoluted.

For reasons that don’t add to the narrative — and in a number of ways, end up detracting from it — much of the action surrounding this year’s attempt to bust out of jail is set in Yemen, in an institution so dank and depressing that it makes the brothers’ previous prison look like a high-end spa. The change of venue might have been worth it if any of the new characters were memorable or at least diverting, or if there were compelling reasons for Michael Scofield (Miller) to be there.

But Michael’s mysterious backstory is kept murky, and despite the fact that Miller gives his usually charismatically contained performance, it’s difficult to work up a lot of interest in why he’s there and who he’s with.

Scofield’s brother, Lincoln Burrows (Purcell), the more rough-and-tumble of the siblings, naturally ends up trying to free his brother, and his storylines end up being even more dark. At one point, a woman who’s helping Lincoln is assaulted by an ISIL terrorist — and that’s after the man has menaced and beaten her. The array of cartoonish and problematic Middle Eastern characters weigh down “Prison Break” and don’t help its attempts to create crisp forward movement.

The best thing about the new series are colorful performances from Knepper and Adelstein, who play T-Bag and the slimy Paul Kellerman, respectively. They continue to bring just the right approaches to their scene-stealing characters, and Knepper in particular is a treat every time he turns up. He distracts from some of the aspects of the new season that don’t make much sense (for example, Lincoln seems to be more or less broke, but somehow he finds the endless source of money that he needs to fund the Yemen operation). C-Note (Rockmond Dunbar) and Sucre (Amaury Nolasco) are around, too, but they don’t get much of note to do in the first three hours.

There are apparently reasons that Scofield — who was presumed dead at the end of “Prison Break’s” first run — is alive and wound up in a prison halfway around the world. But this new incarnation doesn’t make those mysteries as tantalizing as they need to be to overlook its reliance on unfortunate stereotypes, an often unpleasant atmosphere, and unexceptional plot turns. “Prison Break” is at its best when it’s an escapist jaunt graced with a few characters and relationships with energy and texture, but the drama finds it quite difficult to establish that groove this time out.