The death of a woman named Mona whose body was dumped in a sand pit leads Grissom and Catherine to a fetish club run by Lady Heather. Since Mona was a dominant, Lady Heather was surprised that her employee was tortured and suffocated to death. This leads Grissom to conclude that the victim was a 'switch', someone who could play both the dominant or the submissive role.

When a body is found in a foam party, he is identified by Grissom and Capt. Brass as the male prostitute Trey Buckman. Meanwhile, Catherine and Nick investigate a decomposed body of the also male prostitute Croix Richards in his apartment. Catherine receives a phone call from Eddie's phone, who is with Lindsey, with poor reception, but soon she learns that Lindsey is screaming and she leaves the crime scene to seek out her daughter. She finds Lindsey in a car in the water but she rescues her. Sara and Det. Vega investigate the case and they suspect that Eddie is dead. Meanwhile Grissom concludes that both victims may have been dead by insulin and they were employees of Lady Heather. Grissom and Catherine visit the suspect Rebecca and meet her husband Steven McCormick that tells to them a weird story. Then he goes with Capt. Brass to Lady Heather's house. Grissom has a personal moment with Lady Heather and when he learns that she is diabetic, he requests a warranty to get her insulin.

A half-naked woman is found half buried in the desert with a branding on her arm. She has no hair and is missing her right hand. The woman turns out to be Lady Heather's estranged daughter. The autopsy reveals that the woman was a victim of an experiment and starved to death. The team investigates the Betz Clinic where the deceased underwent a sleep therapy session for her insomnia.

After an unsuccessful attempt on Lady Heather's life, Sara discovers Gil's prior relationship with her. Meanwhile, Nick investigates the death of a woman apparently hit by a taxicab.

When CSI investigates a homicide that appears to have connections to the S&M world, Gil turns to Lady Heather for help. But is he really there because of his personal problems with Sara and not for the actual case?

Dr. Langston turns to Lady Heather for help in the murder of a woman who acted like a cat, and Nick tries to figure out what caused a pregnant teen to commit suicide after he saves her baby.