For a show whose entire premise is summarized in its two-word title, Prison Break, its fourth season premiering Sept. 22 on Fox, has a very complex story. It is like the old movie serials. Each week, you could watch Michael Scofield (Wentworth Miller) plan one element of the escape, up to a cliffhanger in which it looks like he’s been foiled--until he finds a way out of it next week.