Benson and Stabler race against the clock as they use a gamer's avatar to track down her kidnapper before he hurts her.
Dr Connor Rhodes must deal with his past when he takes care of a family friend; Dr Halstead struggles with a surgery that could impact a young musician's hearing.
Dr Halstead treats a former high school classmate. Doctors Manning and Charles try to treat a young patient who refuses to take medication.
An old friend's heart problems reveal a bigger issue than anticipated; Devon treats a suicidal woman who he thinks might be a good candidate for deep brain stimulation; Billie and Trevor have an emotional reunion.
Iris welcomes an enigmatic ally to their community, while Hope questions the visitor's motives; a message upends the sisters' world view, forcing them to decide between the safety of their home and the uncertainty of the world beyond.