Season 4 of the hit sci-fi series proves pivotal as the Dominion gains the ascendancy and an all-out battle begins between Klingons and embattled space station defenders. Worf (Michael Dorn) is back as part of an insidious strategy by the Klingons. Loyalties ebb and flow throughout the season as the Cardassians become the victims. Gowron, Kor and Kurn reappear, as well as regulars Avery Brooks, Rene Auberjonois and Terry Farrell.b