Nick's stag party is ruined when a lethal traffic accident brings the whole team into the hospital. While the hospital's facilities are stretched to the breaking point, Bremner and Shepherd reach an agonizing crossroads in their relationship.

Monroe and Bremner attempt parallel miracles: curing the epilepsy of a middle-aged woman and accomplishing the heart transplant of a teenage girl. It's just a pity their love lives are about to come unstuck..

Monroe is busy pursuing Lizzie and counseling Shepherd when an awkward, violent woman arrives at St. Matthew's with a deadly crebral aneurysm. The neurosurgeon calls on Bremner to help save her life.

As Shepherd and Witney reel from their liaison, Monroe finds himself without purpose after a catastrophic operation. Grave complications mean Bremner's operation on a five-year-old refugee turns into a race against time.

Bremner and Shepherd's relationship is unravelling, and Monroe finds himself having to choose between his trainees. A woman with an aggressive brain tumor becomes of of the most challenging cases of the neurosurgeon's career.

Maverick neurosurgeon Gabriel Monroe goes head-to-head with this new boss when he elects to operate on a patient with a deadly vascular anomaly. Meanwhile, Jenney Bremner returns to St. Matthew's from maternity leave to find the hospital changed.