1. Second Year
Colonel Ethan Willis joins the team, bringing new techniques and technologies learned in the field of combat to the hospital. Willis and Mike take a helicopter to Malibu to help shark bite victims - meanwhile, Jesse welcomes new residents.
2.Life and Limb
Willis helps a young soccer player injured in a bus crash and a patient's hesitancy to disclose that she's transgender compromises the doctors' ability to diagnose her abdominal pain.
3. Corporeal Form
Willis, Mario and Heather perform a radical operation on a maintenance worker stuck under a boiler that exploded and Angus's father tries to seize power of attorney over Mike, who remains in a coma.
4. Demons and Angels
On Halloween night, Ethan Willis, Noa Kean and Elliot Dixon rush to the scene of a fire at a haunted theatre, where Dr Amanda Nolan - a new psychiatrist at the hospital - and her boyfriend's son are trapped.
After a landslide, the ER is flooded with mud-hit victims, including rescue workers. To make things worse, the entire hospital is put at risk when children with measles are brought in. Meanwhile, Angus gets encouraging news about his brother Mike.
6. Hero Complex
When a college student regains consciousness at the hospital, Malaya must tell her that she has been raped. Willis and Campbell are at odds when a terminally ill woman wants to end her life on her own terms.
7. What Lies Beneath
Willis and Campbell travel to a Russian submarine to treat a sailor who has been wounded in an explosion whilst the rest of the staff at Angels Memorial look after violent criminals who got injured during a prison riot.
8. 1.0 Bodies
Members of a cult who survived a mass suicide attempt arrive at the ER but refuse treatment as their leader preaches salvation through death. Meanwhile, Mario attempts to connect with his late father's girlfriend.
9. Sleight of Hand
Willis, Leanne and Jesse put their lives on the line to operate on an officer with an explosive bullet in her leg. Meanwhile, Mario, Noa and Guthrie tend to a magician with breathing trouble.
10. Ave Maria
A 13-year-old girl who arrives at Angels following a seizure turns out to be Campbell's daughter. Just as she's set to undergo surgery, Campbell learns about Guthrie's Parkinson's symptoms and is furious.
A citywide blackout during a code black leaves the ER staff in chaos and Elliot and Heather are trapped in an elevator with a woman who is about to give birth.
12. One in a Million
Defying Campbell's orders, Leanne uses the hospital helicopter to reunite a family one last time and Willis and Noa find a cellphone app to help them communicate with an autistic girl.
13. Unfinished Business
While taking on a new role as the hospital chaplain, Guthrie considers undergoing a risky surgery to treat his Parkinson's. Meanwhile, victims of an apartment fire arrive at Angels Memorial Hospital.
Ethan and Mario are asked to attend to two injured construction workers who are trapped on a crane platform 40 stories in the air. Meanwhile, the ER staff tend to victims and perpetrators of a school prank gone horribly wrong.
15. The Devil's Workshop
The ER is quarantined when a viral outbreak jeopardises the lives of the doctors and patients and a young girl whom Leanne bonded with a year ago when she lost her father returns to Angels Memorial.
16. Fallen Angels
The doctors of Angels Memorial Hospital partner with the Centre for Disease Control and Prevention and desperately try to find an antidote for the viral outbreak. Meanwhile, Leanne is about to make a life-changing decision.