At Rock Creek Wild Life Park, BILL and TRYSTA make their rounds. Trysta notices that Matilda the Tiger hasn't touched her food in days. Perhaps she's sick. Matilda shows her caretakers there is nothing to worry about. She has been snacking on something else: a human corpse!
BOOTH and BRENNAN arrive at Rock Creek Wild Life Park. Booth wants to take a detour to see the monkeys but Brennan is all business. The victim is a black male. Booth surmises that the victim was drunk, wandered away from his car and became Matilda's meal. Brennan needs everything back at the lab to determine cause of death.
At the lab, Brennan, CAM, HODGINS and CLARK examine the body. As a vegan, Clark is against zoos. He supports the tiger. According to Brennan, the tiger did not kill this man. Cam agrees: the victim bled to death. Someone cut his femoral artery. Hodgins pulls a shoelace from the remains as Angela arrives. She notes that Clark looks "squeezable." Apparently, Angela is attempting celibacy. Clark is uncomfortable so Angela changes the subject, reporting the victim's identity: DR. ANDREW WELTON. Cam is stunned. She and Welton lived together for two years. Cam excuses herself.
At the lab, Booth comforts Cam. Cam wonders about Welton's daughter, Michelle, whom she helped raise. Booth wants a social worker to give Michelle the news. Cam won't allow it. Michelle was like a daughter to her ten years ago. The news should come from Cam.
At the Welton Home, MICHELLE WELTON doesn't remember Cam. Cam tries to console her after giving her the news about her father but Michelle pushes Cam away in favor of the housekeeper. Michelle last saw her father two days ago. She thought he was on call at the hospital.
Booth and Brennan wait in the car for Cam. Brennan is confused because Cam has never expressed interest in children. Booth suggests that maybe Cam put up a wall after "losing" Michelle. One thing is certain: Cam needs to put Welton's murderer in jail. Cam returns to the car. She explains that the meeting didn't go well. She hides her anguish as Booth drives away.
At the lab, Brennan, Hodgins and Clark take a closer look at the victim's fatal wound. They discover particles of mica and other small white flecks. Clark theorizes that the murder weapon gouged the victim. Cam approaches to urge the Squints to work faster. She reluctantly reports that Welton had opiates in his blood. Hodgins suggests that Welton was abusing drugs. Cam angrily disagrees. There is a reason Welton needed medication. The Squints must find it.
At Roosevelt Hospital, Cam and Booth find DR. MAURA BAILEY. Bailey is now the Chief Administrator and an old rival of Cam's. Booth tells Bailey that they believe Welton was killed at Rock Creek Wild Life Park during a hospital benefit on Friday night. They need a list of all attendees. Booth also needs a list of any malpractice suits against Welton.
At the Nurses' Station in the Cardiac Unit, Cam and Booth question NANCY LAUDER, GRETCHEN KUJAWA and LAUREN DOBBS. The women tell Booth and Cam that nothing unusual happened before Dr. Welton went to the benefit. Did he have a date? Dr. Welton could have taken anyone to the party. "He wasn't the type to settle down," comments Nancy.
At the lab, Angela finds Hodgins working with a sample from the victim's clothing. Angela likes the smell. Hodgins tells her it's urine. She realizes celibacy is doing strange things to her. Hodgins suggests she join a gym to burn off excess energy.
Brennan reports to Cam in the Autopsy Room. She found bony growths on Welton's thumbs. He had synovial chrondromatosis, a condition that requires painkillers. It would have made it dangerous for Welton to operate. Cam takes a call from Booth. A man named Brandon Casey sued Dr. Welton because his wife died during an operation. Dr. Welton won the lawsuit and filed a restraining order against Casey. Yet, Casey bought a ticket to the hospital benefit. He was there the night Welton was murdered.
At the FBI, Booth interrogates BRANDON CASEY. Casey admits he was angry after his wife died but he saw the error of his ways. Casey went to the benefit to apologize to Welton. He was ready to move on. However, they never got a chance to talk because Welton was arguing with a woman. Booth asks for a description but Casey can't remember anything about her. Sweets believes they can retrieve the information through hypnosis.
At the lab, Brennan and Clark find defensive wounds on the bones. Angela appears. Clark fends off Angela's advances, telling her his sexual needs are fulfilled. Angela presents a scenario based on the measurements of the injuries. The injuries were caused by someone between 5'7 and 5'11, brandishing a five-foot pole. Sweets enters, looking for Angela. He needs a sketch artist.
At the FBI, Sweets hypnotizes Casey. Using his voice, he brings Casey back to Rock Creek Wild Life Park during the hospital benefit. He coaxes him until Casey can clearly see the woman arguing with Dr. Welton. Casey describes her as Angela sketches.
At Roosevelt Hospital, Booth and Cam show the sketch to Bailey. She recognizes the woman as Diane Annenburg, one of the hospital's generous donors. Was Annenburg upset that Welton was operating while ill? Bailey clarifies that Welton wasn't operating. He was supervising. What was the argument about then? Her son, Rick Annenburg, applied to Roosevelt for his surgical residency. Dr. Welton rejected his application. Since Diane Annenburg was pouring money into the hospital, this did not make her happy.
At the FBI, Booth talks to DIANE ANNENBURG. She brushes off her argument with Welton. She was simply telling him how disappointed she was that her son would not be participating in the residency program at Roosevelt. Her son deserved to be in the program. He was second in his class. Annenburg wanted Welton removed from the Board of Admissions but she would never kill him. Perhaps not, but would her son?
At the lab, Brennan and Clark catalog injuries while Cam observes. Brennan asks about Michelle -- Cam guesses they will move her to a foster home. Hodgins enters with news: the small white flecks from the body are bits of a plastic knife. Cam remembers that they found a shoelace in the remains. Perhaps the killer tried to save Welton. He used a plastic knife to enlarge the wound and the shoelace to tie off the femoral artery to stop the bleeding. Despite its failure, the procedure suggests that the killer has medical knowledge.
At the FBI, Booth questions RICK ANNENBURG. Rick claims that Welton helped him by rejecting him from the residency program at Roosevelt. Now he can go to a program elsewhere and get away from his mother. Rick knows that if someone tried to tie off Welton's femoral artery, they would be covered in blood. Booth can check his clothes. He is innocent.
At the Welton Home, Cam visits Michelle. Michelle admits that she remembers Cam, but she doesn't know if she can forgive her for leaving. Cam tries to explain that she and Welton were going to get married. Welton was still seeing other women though. He couldn't commit to Cam so she had to leave. Michelle suggests that Cam wasn't good enough for her father. She tells Cam to go. After Cam walks away, Michelle breaks down in tears.
At the lab, Angela and Brennan have coffee with Cam. Cam describes what Michelle said and why she left Welton. Brennan realizes that if Welton cheated on Cam, he could still be seeing more than one woman. Angela agrees because men are awful. Hodgins approaches and, while the women glare at him, reports that the urine on the victim's clothes came from a lion, not a tiger. What's more, what he thought was mica turned out to be snake scales.
On the Forensic Platform, Hodgins shows Booth and Brennan pictures of Rock Creek Wild Life Park. There are no lions in the park but their urine is used to keep these the capybaras in their enclosure. Near the capybaras, there is a reptile shed. In the photograph, Brennan sees a snake hook. This could be the murder weapon.
Meanwhile, Clark brings a visitor to see Angela in her office -- DR. NORA OLDHOUSE, Clark's "romantic partner." He hopes this will help Angela see that he is unavailable and her advances are unwelcome. An understanding Dr. Oldhouse offers Angela advice. "In the absence of a sex partner, there are other alternatives. Vibrators or sex toys..." Clark excuses himself.
At the FBI, Cam and Booth have a talk with LANGSTON, the clerk at the motel Welton and Cam used to frequent when they wanted to get away during work. It turns out not much has changed. Langston tells Cam and Booth that Welton had been frequenting the motel with someone else as of late: Dr. Maura Bailey.
At the FBI, Booth and Brennan present Bailey with the snake hook. Bailey has never seen it before. Booth wants her to prove it by letting them test the clothes she wore to the benefit. Bailey declines. They don't have a warrant. Brennan mentions they know about her affair with Welton. They'll talk to her husband. Bailey won't be blackmailed. Booth and Brennan can talk to her through the hospital's lawyer from now on.
Cam sits at the lab with a salt and pepper shaker. Brennan approaches to talk about the case but Cam isn't in the mood. Cam explains that she had a set of salt and pepper shakers that fit together. She gave one to Michelle before she left her and kept the other one. She told Michelle that whenever she looked at her half, Cam would be thinking about her. Brennan suggests that Cam take Michelle in now. She is an orphan. She needs someone to look after her.
In Angela's Office, Brennan and Angela look through photographs from the hospital benefit. They rule out Dr. Bailey as the killer. Her dress is white and would have shown blood. Angela spots a snakeskin purse in the crowd. She magnifies the image. The purse has a tear. Angela moves through the photographs until they see the owner of the purse: Nancy Lauder. She's wearing a black dress.
At Roosevelt Hospital, Brennan, Booth and Cam confront Nancy Lauder. She knows she's caught and admits to burning the dress. Nancy was dating Welton when she found out he was sleeping with Bailey. She expects Cam to understand but Cam can't empathize with what Nancy did.
At the Welton Home, Cam tells Michelle that they caught the person who murdered her father. She produces her half of the salt and pepper shaker set. Cam asks Michelle to live with her. Michelle doesn't respond. She runs out of the room. Cam is heartbroken. She moves to leave but Michelle returns...with her shaker. She fits them together and runs to Cam. They hug just like the salt and pepper shaker set.