In the season finale, dispatch errors send medics to the wrong locations. Meanwhile, Boone plans a party for Tyler's birthday; Marisa's reunion with a friend from the Army goes south; and Nancy considers the future of her relationship with Rabbit.
A patient (Richard Kind) who regularly abuses the system calls again for help; Nancy has problems with her father's new job as head of the trauma center; Boone disagrees with Tyler on how to treat a patient at a mosque; and a dream about Rabbit has Marisa unsettled at work.
Nancy goes against procedure when treating a cheerleader, which puts her relationship with Joe at risk when he suffers the consequences of her actions. Meanwhile, Rabbit and Marisa are exposed to meningitis and must be quarantined; a misunderstanding results in tension between Boone and Tyler.
Rabbit's therapy starts to pay off when he recalls a traumatic occurrence from his past. Meanwhile, a patient suffers because of Nancy and Diana's opposing opinions; Glenn achieves a career milestone; and Boone and Tyler think about their futures.
Glenn loses a patient during a routine procedure; Boone and Tyler's patient flees their rig; Rabbit starts his mandatory therapy sessions as things between him and Nancy heat up; and Marisa adjusts to her new partner.
A construction worker becomes trapped underground after stumbling down a manhole, and Nancy's phobia hinders his treatment. Elsewhere, Rabbit and Marisa care for victims of a bank robbery; and Boone makes a critical decision in his new position that threatens a coworker's career.
Glenn questions Nancy's handling of a heroin user after a deadly batch of the drug makes it to the streets. Meanwhile, Marisa deals with an unusual theft, and Boone makes a move toward changing his future.
A plane full of holiday travelers must make an emergency landing, but things go horribly awry. Meanwhile, Nancy has reservations about seeing her family for Thanksgiving; and Boone and Tyler deal with an unusual yet typical Thanksgiving emergency.
A man goes on a shooting spree inside an office building, and the ensuing hostage situation impacts Boone directly. The crisis forces Rabbit and Nancy to work together for the first time in more than a year. Meanwhile, Marisa notices she has more in common with Rabbit than she thought.
A medical drama centering on first-responder paramedics at a San Francisco hospital and the extreme dangers they face to save lives. In the series opener, a tragedy impacts the team directly---and permanently. Cliff Curtis, Derek Luke and Anastasia Griffith star.