In this episode of CSI, the following happens. We open with a prisoner being granted a new trail, after he was sent to prison over 18 years before for murder. The CSI on the case was Catherine, and it was her first solo case. And so Catherine judgement on the case is being called into question and so everything from the case is now being re-tested.
Since the prisoner was convicted due to only one piece of key evidence, he is calling for this piece of evidence to be thrown out. This is due to the fingerprints on it being only a 5 point match, which today wouldn't be enough to convict someone on. When Catherine re-runs the prints from the rock, it matches that of the prisoners. Soon Catherine discovers a hammer in a nearby tree, which has been there since the murder and so it appears as though they have found the murder weapon. They find prints on the hammer, which are in blood, but when the prints are run, they don't match the prisoner's prints. Soon the prisoner admits that his prints are on the rock, as he used it to break into the victims house to rob him, but when he found the dead body on the floor, he made a run for it. He had already broken into 2 other houses that same night. Soon the team track down one of his friends, who they believe may have been involved in the murder. We soon learn that they weren't just friends, but actually boyfriend and girlfriend. She got pregnant by him and they were stealing to get money to move away. Soon they can prove that her prints are on the hammer. She then learns from Brass that anyone involved in the case will be sent to prison, for life, whether or not they swung the hammer. She confesses that the prisoner killed him with the hammer and that she simply walked in after the murder had taken place. He says that he wanted a new trial, as he wanted a fair trial; even though he knew he was guilty. He also admits that he is angry with Sabrina, his girlfriend at the time, as she never went to visit him and he didn't even know what happened to the baby she was pregnant with at the time.