Matt Phelps sends his two kids to bed, and out of the blue, there is a drive-by shooting and his daughter Aimee is shot and killed in her bed. Grissom, Warrick and Capt. Brass investigate the case and Grissom learns that Matt Phelps is Warrick's mentor and friend. Warrick's investigation is conducted based on his emotions instead of on the evidences with serious consequences for Matt and a suspect. Meanwhile, Nick and Sam Vega investigate the mysterious death of a boss of a four-men Internet service company in the air-conditioned servers' room. They find many secrets in the team but no suspect and no murder weapon. Until Nick observes the duct of the air-conditioning.

When Joanne Crooks is assaulted without rape at home, Catherine, Grissom, Nick, Warrick and Capt. Brass assume the investigation. They find fingerprints on the windows and they learn that the criminal is escalating in his crimes. They fear that he soon will rape his victim since this was his first break in. Meanwhile, Sara learns that the paraplegic prosecutor Melissa Winters will be submitted to a surgery of high risk. Three years ago, Winters was shot on the neck in a home invasion where her husband as killed, but the murderer has not been found. Now the bullet has moved and she needs the surgery. Sara decides to reopen the cold case using the bullet withdrawn in the surgery to try to find the criminal.

Fingerprints suggest a link between two home invasions, but it's hard to link either the victims or the logical suspects, who may all be innocent. The crucial survivor testimony proves the most tenacious problem. A toddler found and accidentally fired a murder weapon in the family's suburb garden. Its place is a mystery, being so overt and unrelated to the victim, a bounty-hunting has-been, until the team consults the sky.

After a massive shootout between the LVPD and a Latin American mob gang, the CSI team have to find and process hundreds of bullets to determine exactly what happened.