Greene flies to San Diego when his father runs away from his retirement home. Former med student Deb Chen, now known as Jing-Mei Chen and also a full-fledged doctor, returns to the ER. On her first day, she and Carter help a young Jane Doe brought in for panhandling. Corday tries to coerce Dean Rollins into revealing the location of another body. He asks her to end his suffering. Kovac tries to help two brothers, one of whom is mentally challenged. Finch treats a young teenager who may have too much on her plate. Dr. Dave tries to fix Weaver's car, and has to break bad news to a young kid.

Third year med student (and part-time OB nurse) Abby Lockhart begins her ER rotation. A flu bug sweeps through the ER. Carter tries to help a kid with muscular dystrophy while Cleo treats a kid who's been injecting hormones into himself. Corday discovers that her mother will be coming to town and then decides to pay her a visit. Lucy treats a dying homeless man. Benton and Romano clash over the treatment of a surgical case. Luka and Carol treat a young boy whose mother is injecting him with saline to get surgical procedures done.