In the fifth-season premiere, a new resident, Kayla Thornton (Tamera Mowry), joins the Rittenhouse staff. Meanwhile, as Ben and Lu's romance deepens, he receives shocking health news and a visit from his ex-wife (Robyn Lively), who is seeking work at the center; and a friend of Jesse's talks her into getting high on cough syrup with devastating results. Andy: Patricia Richardson. Lu: Rosa Blasi.

Rozanda "Chilli" Thomas plays a pop star who is accused of molesting a child whom she befriended when she and the girl were being treated at the clinic. Andy: Patricia Richardson. Lu: Rosa Blasi. Nick: Brennam Elliott. Ben: Grant Show. Peter: Josh Coxx.

Rittenhouse inadvertently distributes baby formula that is missing a vital supplement and is causing a beriberi outbreak among infants. Meanwhile, one of Andy's patients is in need of a kidney transplant and the perfect match is her mother's rapist, her biological father. Lu: Rosa Blasi. Ben: Grant Show.

While on a much needed vacation with Milo, Andy uncovers a cancer cluster. Meanwhile, at the clinic, Lu deals with a pregnant bodybuilder who refuses to have a C-section, and treats a high-school basketball star for ADD. Andy: Patricia Richardson. Lu: Rosa Blasi.

Andy treats a judge who is suffering from hearing loss and discovers that his condition was caused by pain-medication abuse. Meanwhile, some elderly patients die under mysterious circumstances. Ben: Grant Show. Lu: Rosa Blasi. Peter: Josh Coxx.

Andy treats a breast-cancer survivor who has developed body dysmorphic disorder, which makes her preoccupied with her appearance. Andy: Patricia Richardson. Kayla: Tamera Mowry. Lu: Rosa Blasi.

Cardiologist Delia Marshall has two major tasks when she assumes Dr. Morton's position at Rittenhouse, handle his workload and take his place on the review board, meaning she has to weigh judgment on her friend, Andy, who's accused of failing to treat a patient. Lynn Whitfield.

Lu discovers that two girls who are bullies at their high school are being poisoned by another student. Meanwhile, Andy is asked by a friend to endorse her heart-health diet book, only to have her come to the clinic with chest pains. Andy: Patricia Richardson. Lu: Rosa Blasi. Nick: Brennan Elliott. Kayla: Tamera Mowry.

Lu gives physicals to employees at a soft-core porn production house and finds rampant venereal diseases. Meanwhile, Kayla treats a teen for a gunshot wound, and he asks her not to report his condition to the police. Lu: Rosa Blasi. Kayla: Tamera Mowry.