Fox has picked up Prison Break for a third season - but earning that green light was no easy feat for the serialized thriller that, having busted its cons out of the clink at the end of Season 1, ran the risk of exhausting not just its fugitives, but its storytelling options. Coming up with a winning Season 3 setup "was absolutely the toughest nut to crack thus far," series creator Paul T. Scheuring tells TVGuide.com. "We always had the first two seasons mapped out in concept, and felt we'd cross the bridge of Season 3 when we got there."

What did Scheuring come up with? Understandably, he says, "There's not too much we can divulge. But by the end of the season finale [filmed last week and airing April 2], people will understand where the characters stand, and we leave a lot of mysteries on the table."

And which characters will be standing at the sophomore run's end? "More than half of the cast members will be back, and they know who they are," says Scheuring. "But I can't reveal more than that."

UPDATE: Emerging details include the addition of at least four cast members - two men, two women, none American - says Variety.

For much more on Prison Break's third season - including where it will be filmed, and how Sarah Wayne Callies' pregnancy may have changed up the game plan - see Interviews & Features.