A woman is found outside of her apartment complex, in a bloody nightgown, pounding her hands on a dead woman's chest, causing blood to ooze from a gaping abdominal wound. Mac and Stella find a bloody wooden stake next to the victim, Rachel Camden, and muscle tissue from Rachel's heart under her apparent killer, Ophelia Dichiaria's, fingernails. Mac learns Ophelia is a parasomniac, and was sleepwalking when she was found with the victim. Using video surveillance of the apartment lobby, Mac discovers a large shadow behind Ophelia as she exits the building, and using corneal imaging, capturing details reflected in the eye's cornea, Mac identifies witness, Jason Walder, who was playing basketball nearby. Splinters from the wooden stake are found in Jason's hands and a condom in his wallet contains identical lubricant found inside Rachel. Rachel was having an affair with Jason, and when she ended it to start a family with her husband, Jason killed her. Mac learns Ophelia was trying to massage Rachel's heart, mimicking the memory of trying to save her son's life, who died in a car accident with her husband. Danny and Aiden investigate the murder of 'professional' pickpocket, Lenny Cook, who was beaten and robbed, with the exception of several Australian hundred dollar bills hidden in a secret pocket and a number of dimes found near his body. They ultimately discover a member of Lenny's pickpocketing crew suspected him of skimming and set Lenny up to pickpocket a "mark" carrying Australian bills. When Lenny didn't give his partner his correct share, he beat Lenny to death with a roll of dimes in his fist that broke, littering the crime scene.