Several freshman shows from last season are being remodeled and relaunched this fall, and some long-serving veterans are getting a tuneup as well. Here's a rundown of the changes that will be made to notable veteran shows and to members of last year's freshman class:

"Chuck" (returns Sept. 29 on NBC): One of my main quibbles with this otherwise charmingly goofy adventure show was that I couldn't see a way around this problem: What if the spy secrets that had been accidentally downloaded into the hapless Chuck Bartowski's brain became outdated? That issue will be addressed head-on, as it were, in Season 2, creator Josh Schwartz said in July at the Television Critic Association's press tour. "We actually play with this going right into the first episode this season . . . this idea of when the government rebuilds the espionage-related Intersect computer, Chuck will become expendable and it will be left to Casey, Adam Baldwin's secret agent character, to 'disappear' him, as they say in the NSA." That arc will play out all season, as will a romantic story line featuring the charmingly nerdy Chuck and his CIA handler, Sarah Walker.

"CSI" (returns Oct. 9 on CBS): In the ninth episode of the season, Laurence Fishburne will make his first appearance. Fishburne is the new lead on the show, replacing William Petersen, who's leaving after episode 10. Fishburne will play a criminologist who is consulted by the CSI techs and eventually joins their team. The new character, who is as yet unnamed, thinks he may have criminal tendencies himself. He is "trying to use the world of solving murders and violent killers to understand his own soul," executive producer Naren Shankar said in a July interview.

"Desperate Housewives" (returns Sept. 28 on ABC): The show's fourth-season finale ended with a jump five years into the future, a move that creator Marc Cherry said was driven by the show's overly Byzantine plots. Soap-opera entanglements tend "to build up and . . . I wanted to get back to where we were that very first season, where it's just the problems of some ordinary women and they were small and relatable," Cherry said in July at a TCA panel.