Mark, with surprise guest Cynthia, returns to San Diego to be with his ailing mother. While trying to diagnose his mother's condition, Mark decides that he and Cynthia have no future together and tries to come to terms with his seemingly distant father, and learns why he was never promoted to Admiral.

Several heroin ODs are brought into the ER, including Chase Carter. Mark tries to track down Cynthia. Anna treats a John Doe sent from another hospital because he had no insurance. Doug accuses two parents of child abuse, but finds out that their child is disturbed. Benton and Corday run into his sister Jackie. Scott Anspaugh finishes his chemotherapy.