Strahovski) to retrieve a copy of the Intersect, while the NSA sends then-Major John Casey (Adam Baldwin) to capture Chuck. The two agents eventually cross paths, and Sarah fends off Casey. They then discover that Chuck is a human version of the Intersect who sees a rapid-fire series of images (or "flashes") of intelligence from the Intersect database whenever his brain recognizes a bit of related information with his own eyes or ears. The two agencies conclude that Chuck must be protected and assign Sarah and Casey jointly to the task. Series development Chuck is the lead character on the show. Thus, major seasonal plot arcs generally revolve around the weekly missions that Chuck, Sarah and Casey engage in, as well as Chuck's relationships with Morgan Grimes (his best friend and co-worker), his fellow Nerd Herders and co-workers, his sister Ellie and her boyfriend (later husband) Devon. Chuck is also very worried about his future and wants desperately to remove the Intersect from his brain, although by the beginning of season three he has come to accept his role as the Intersect. Chuck is often involved in the major and secondary episodic plots and the two sometimes intertwine. Sarah Walker A major thread throughout the series is that Chuck is in love with his CIA protector Sarah, who is pretending to be his girlfriend as part of her cover story. The two characters continue to become closer despite frequent setbacks and constant resistance due to their circumstances. Sarah is depicted as slower to recognize her own feelings toward Chuck than the other way around, and for various reasons has been reluctant to voice her feelings. Despite Sarah characteristically hiding her real feelings, several other characters have detected a genuine attraction and pointed it out, as early as "Chuck Versus the Wookiee" when Carina (Mini Anden), who is familiar with Sarah, tells Chuck that Sarah wants him, though she probably doesn't even know it yet. Sarah and Chuck have shared kisses under unusual circumstances in "Chuck Versus the Imported Hard Salami" and "Chuck Versus the Seduction". In the former case, Sarah kisses Chuck seconds before the countdown on what they believe to be a bomb reaches zero. In the latter case, Seduction trainer Roan Montgomery (John Larroquette) quickly discerned that there was more than a working relationship between Chuck and Sarah. Sarah maintains that it would be unprofessional of her to