A city-wide blackout sends the hospital into total darkness. Bash treats a rock climber who fell from a cliff. Dr. Bishop and Bash make a major career decision, putting their futures on the line together. June is finally forced to face her father. Theo goes above and beyond to treat a deaf child, while letting frustration get the best of his spiralling personal life. Claire struggles to find footing in her new role as a nurse practitioner, and Mags pays a visit to a former mentor.