When a private jet lands after a party, they find the trainer Lori Hutchins dead apparently stomped by the horse in the cargo bay. Grissom, Catherine, Nick and Capt. Brass investigate the case. The horse is in quarantine and the veterinarian Dr. Stevens help Catherine to collect material from the animal. They interview the owner of the jet, guests and crew and find two tranquilizers dart in the cargo bay. When the horse mysterious die, Dr. Robbins make the autopsy and they learn what happened in the flight. Meanwhile, Sara, Warrick and Det. Lockwood investigate the suicide of a teenager in the middle of the desert. When they find a second body dead in the same circumstances, they believe it was a kind of "Romeu and Juliet" pact of the younger. Then they identify the couple, Toby Wellstone and Jill Frommer, and interview her mother trying to understand why they died in a distant place and separated from each other.