In the series finale, Proctor and Zambrano each question their ethical boundaries when faced with difficult decisions concerning the lives of their patients. Meanwhile, Deleo's brother unexpectedly reappears.
Several divers are injured while exploring an underwater wreckage, and the tragedy causes Serena to face one of her biggest fears. Meanwhile, Deleo and Zambrano become overly curious about a new woman in Proctor's life.
A hurricane bears down on Miami as the Alpha team members treat victims of a massive car accident. As the storm nears, the need to evacuate becomes more critical. Meanwhile, Zambrano's father visits the hospital.
The team tries to save the lives of a couple who where injured when a balcony collapsed, but is baffled when the wife doesn't want to be treated; and a patient in possession a large sum of money has everyone talking.
Members of a wedding party are seriously injured when a tent collapses on them, and the surgeons discover they share surprising connections with the victims. Meanwhile, Chris and Eva's playful flirtation draws attention from their colleagues.
Several people are shot by a gunman at a hotel's outdoor restaurant, including an asthmatic woman who works as a waitress there. Her medical condition complicates her surgery when it's discovered her asthma is caused by a tumor.
A team of surgeons works trauma cases in a Miami hospital. In the opener, a gas explosion at an ice-cream shop seriously injures a pregnant woman and her husband. At the hospital, the chief surgeon (Andre Braugher) suddenly quits, leaving his staff in shock. Stepping in is a mysterious physician (Jeremy Northam) newly arrived from Baltimore who once worked as a military surgeon.