"A House Divided" is the 25th and final episode of the third season (1979–80 season) and 54th overall of the American television series Dallas. It is the episode known for spawning the eight-month "Who shot J.R.?" phenomenon. The episode ended with the mysterious shooting of J.R. Ewing (Larry Hagman) in his office by an assailant that would not be revealed until the following season. The mystery was resolved in the fourth episode of the following season, entitled "Who Done It", which remains the second most-watched episode in American TV history.