The Death Song of Uther Pendragon (S05E03)

When a mysterious figure grants Arthur the ability to bring back the dead, the king faces a conflict between his emotions and reason. Unable to refuse the allure, he chooses to communicate with the one he longs for the most—his father, Uther Pendragon. However, the realm of spirits is treacherous, and Arthur is unaware that this choice carries severe consequences. With time running out, Merlin must rectify Arthur's error to save Camelot and protect everything they’ve worked for from impending doom.