The CSIs investigate the murder of a woman who rode her horse at a local stable and was a former sorority queen in college. At first they suspect a sorority sister, but when she too is murdered, the team realizes the killer is sending a message. After the CSIs discover that the two murdered women kicked the stable owner's daughter out of the same sorority years ago, they suspect the woman finally got her revenge on her harassers. However, when the killer's DNA is found on the first victim's horse, it's revealed to be the woman's father, who couldn't stand the way the sorority girls broke his daughter's confidence years ago and then resumed their torment at the stable. After he is arrested, the daughter tries to hang herself, but Horatio gets there in time to save her. In the end, Horatio gives her the hope and confidence to start a new life.