Sean and Christian's longtime friendship and budding business partnerships are tested when family man Sean discovers that playboy Christian has accepted money from a wanted Colombian drug kingpin for a surgical procedure. Furthermore, the troubles at work along with a strained relationship with his wife, Julia, are pushing Sean into a midlife crisis.
While Christian deals with feelings of sexual inadequacy, he finds himself faced with the daunting task of making two identical twins look different from one another.
Christian must use his sexual penchant to appease a loyal female client who has had a surigcal tool accidentally left inside her. Grace and Sean must deal with a volatile patient named Nanette who wants plenty of work done before a big high school reunion.
Christian and Sean are heavily affected by an operation performed on an aging adult film actress, and Sean decides to try livening up his sex life with Julia. Matt attends a porn party with Christian and gets an education on being with a woman. Sean offers help a transvestite catch a doctor who's been giving unsafe and illegal sex change operations, while Julia makes the decision to return to medical school.
Christian has an encounter with a former lover and ends up at a sexaholic group meeting. Asking for Grace's help, he begins to take a deeper look at the way he's treated women in the past. Meanwhile, Julia discovers she's pregnant, putting into question her ability to continue as a medical student.
Christian finds his most cherished posessions vandalized and sets out to find the guilty party among the previous women in his life he may have wronged, an act which causes him to reassess his past behavior towards women. Sean finds a new sense of excitement when he meets a new patient. Meanwhile, Matt agrees to help Vanessa piece back together her relationship with her girlfriend Ridley.
Sean and Julia begin to explore the attraction they have for other people when Sean gets a message from former patient Megan O'Hara, and she coaxes Sean into bringing in Jude as an intern at the practice.
Christian decides to take action after learning one of his patients had work done in order to conceal an identity as a criminal. Matt inadvertently hits a girl with his car after smoking marijuana, but doesn't realize it until seeing an article in the paper the next day.
Christian reevaluates his relationship with Kimberly when Dr. Bobbolit makes him an enticing offer. Sean finds out that his relationship with Megan O'Hara comes with serious consequences, while Julia gets deeper with Jude and begins to think she doesn't know him as well as she thought. Meanwhile, Liz bonds with Sofia Lopez while helping her through a transitional period.
Sean and Christian must get recertified, which forces Christian to be at the top of his abilities. Sean is also forced to deal with the downturn in Megan O'Hara's health. Meanwhile, Mrs. Grubman comes in with the new man in her life for some minor touch-ups, but realizes her life lacks direction.
Sean and Christian unpleasantly learn that one of their patients has a multiple personality disorder after performing a procedure on her. Gina suddenly returns with news that could turn Christian's world upside down. Meanwhile, Cara Fitzgerald goes back to school after recovering from the accident caused by Matt and Henry.
A patient's surgery brings an encounter between Sean and Christian and a friend from the past. Meanwhile, Christian and Gina are unable to come to terms with the status of her pregnancy, while Sofia Lopez and Julia begin to get to know one another.
Christian and Sean find their lives and business being further ravaged by Escobar Gallardo's drug-trafficking business, as they must perform more and more illegal surgical procedures.