I don't remember much about the story, only that Charlie was kidnapped from CalSci while in his office, I think. The guy held a gun against his side, and was taking him to the car. He was supposed to have lunch with Larry, and Larry saw Chalie, so Charlie was able to give him a coded message. it was: "Take care of my 2:35 class."  Charlie didn't have a class, and it was actually a date for then FBI caught the guy. I think the guy tied Charlie to a bed, but I'm not positive. And I think Don wasn't allowed to be part of the rescue team since it was personal. 

Any ideas?

Found! No Good Deed by Ellis.