November sweeps is a big time in television; it’s a time when big names and big plots often collide in big ways. CSI is going to follow the pattern and bring in a terrific actress whom you might know from Back to the Future, or perhaps more recently on Switched at Birth. I am, of course, referring to Lea Thompson. She’s a joy to have, even if only for a single episode. I’m surprised they didn’t cast her for the 300th episode, but I suppose that one was already bursting with guest stars and anymore would’ve capsized it. And by capsize I mean ruined it by having way too many characters running around.

Thompson will be playing a smart, no-nonsense woman ­– name currently unknown – with a rich history. According to THR, she knows her way around a CSI lab and has worked many crime scenes in Detroit. These days she’s a defense criminalist and will be working closely alongside Finlay (Elisabeth Shue). How close? That’s a good question and it’s one I don’t have the answer to. The information isn’t exactly clear on what her role will be in the episode other than she’ll be there. The assumption is she’ll be working on a case, but even that’s not a foregone conclusion. She could be in the episode for a reason unrelated to a crime.

Because there’s always some sort of a twist when figuring out who the killer is in any given CSI episode, wouldn’t it be something if Thompson’s character turned out to be the surprise bad guy? Like, from completely out of the blue. She could be there visiting Finlay while the usual case-of-the-week is underway, and then suddenly a piece of evidence surfaces that links Thompson to the murder. Everyone will be like “What!?” And they’ll scratch their heads for minute at how ridiculous it seems before throwing her in a cold cell.