An old friend's heart problems reveal a bigger issue than anticipated; Devon treats a suicidal woman whom he thinks might be a good candidate for deep brain stimulation; Billie and Trevor have an emotional reunion.
A warlock who triggered the Salem witch trials escapes purgatory; Abbie tries to regain trust in Frank Irving; Henry searches for his identity.
Mac and Riley battle through a war-torn region occupied by rebels as they fight to get oxygen to a children's hospital.
Sheriff Buck becomes the target of revenge after he refuses to help a radio talk show host get on television; Caleb wants to mark Merlyn's passing.
Nick investigates a series of mysterious burglaries; Leigh loses an important package; outside the Gates, Claire has a chance meeting with an old friend; and Lukas helps Brett blow off steam.