After a bitter custody battle, shots are fired outside the courthouse. Bullets fly and the target is the little girl's mother. Horatio goes after the father, who he suspects may not be the girl's biological father after all. However, when the mother's shady past is uncovered, the team finds that she has a lot of enemies who would like to take a shot at her. Meanwhile, Calleigh's father returns to the crime lab for her guidance but for an unexpected reason.

A former high school football star is murdered at a reunion, the CSIs must find the killer. The victim was the big man on campus in high school and there are a lot of guests at the reunion with reasons to resent him all these years. Now, the team must investigate everyone, from the head cheerleader to the school misfit, to see who held a decade-old grudge big enough to kill. Meanwhile, Horatio and Delko arrive at a crime scene and discover that it's already been processed, leading Horatio to uncover further information about his brother possibly being alive.

An axe murderer on death row is given a stay of execution just moments before it was to take place, on the grounds that there may have been tainted DNA analysis used at his trial. Now, without using any DNA evidence, the team must race against time and reexamine all of the physical evidence in the case, just as they get a call on a new double murder that looks suspiciously like the case they're working on.