The team responds to a major accident when a car loses control and crashes into a local street fair. Meanwhile, Nancy gets a new partner, and Rabbit teaches Marisa a lesson.

Boone's marital problems take a back seat to a mad gunman who goes on a shooting rampage inside an office building. The incident forces Rabbit and Nancy to work together for the first time in over a year to treat the injured hostages. Meanwhile, Marisa realizes she's more like Rabbit than she would care to admit.

Tyler and Boone respond to an explosion at a Chinese restaurant and find that there is more to the situation than meets the eye. Meanwhile, Nancy's advanced medical training is put to the test. Elsewhere, Rabbit has an unexpected reaction to a bumpy flight.

Tyler and Boone are on the scene when chaos erupts at a Halloween party. Meanwhile, Nancy and Glenn's shift takes an unusual turn. Elsewhere, a secret is revealed that can change a partnership.

The tables have turned as Nancy and Glenn find themselves on the other side of the trauma. Meanwhile, Boone's priorities on the scene are called into question. Elsewhere, Rabbit has a surprising reaction while treating a patient.

Glenn's attempt to follow his heart puts his career – and safety – on the line. Meanwhile, Marisa gets a surprise visit from an old friend. Elsewhere, Rabbit helps a patient deal with his devastating loss.

A wedding celebration at sea is interrupted by a high-speed boat collision. As the team quickly rushes to their aid to treat the victims, things get lost in translation. Meanwhile, Nancy takes time to reconnect with her family. Elsewhere, Marisa comes to the aid of those close to her heart.

Thanksgiving travel gets dangerous when a packed commercial airliner must make an emergency landing that goes terribly wrong. Meanwhile, Nancy finds herself reluctant to spend the holiday with her family. Elsewhere, Boone and Tyler respond to an unusually common Thanksgiving emergency.

As a bad batch of heroin hits the streets of San Francisco, Glenn questions Nancy's judgment during an encounter with a "frequent flyer." Meanwhile, a bizarre theft sends Marisa on wild goose chase. Elsewhere, Boone contemplates his future and takes a new step, while a romance begins to take off.

Glenn handles a procedure by the book and loses a patient, bringing the whole station under a "probie curse." Meanwhile, Rabbit's suspension leads him to mandatory therapy sessions to regain his wings as his relationship with Nancy intensifies. Elsewhere, Marisa deals with a new partner, while Boone and Tyler have a patient jump out of the rig.

Rabbit has a breakthrough in therapy that reveals a traumatic event from his past. Meanwhile, Nancy and Dianas difference of opinion puts a patients life at risk. Elsewhere, Tyler and Boone consider their futures, as Glenn reaches a career milestone.

Nancy and Glenn get caught in the crossfire as a sniper takes San Francisco hostage. Rabbit and Marisa are torn between instinct and protocol as each emergency medical call could be a trap. Meanwhile, Boone must learn to adapt to Tyler's new paramedic status and medical knowledge.

Nancy comes under fire for ignoring protocol when treating a high school cheerleader and her actions put Dr. Joe in the hot seat and their relationship on the line. Meanwhile, Rabbit and Marisa are quarantined after being exposed to a patient with meningitis. Elsewhere, a misunderstanding puts Boone's partnership with Tyler to the test.

A patient who regularly abuses the system calls again for help. Nancy has problems with her father's new job and Boone disagrees with Tyler on how to treat a patient at a mosque. Also, a dream unsettles Marisa at work.

In the process of gathering stories for his book, Glenn finds himself discussing unusual calls with his work mates and ends up hearing much more than he imagined. Elsewhere, Tyler's dad comes to town for a visit.