Following the destruction of the Xindi weapon, the Enterprise crew discovers that they have been sent back in time to 1944. However, history has been altered, leaving Nazi Germany in control of a large portion of the eastern United States.
T'Pol and Archer confront the Syrranites and meet T'Pau who denies the embassy bombing. Archer, who has Surak's essence, is asked to help. V'Las threatens Enterprise to make sure an attack on the Syrrannites isn't witnessed.
Enterprise escorts Tellarites to peace talks with Andorians. While transporting they rescue Andorians and say the Tellarites attacked them. Enterprise is soon attacked by an Andorian ship, and Archer must prove who is responsible.
While Enterprise is visiting Earth, Phlox is abducted by the Klingons and forced to research a cure for a virus destined to wipe out the race. Reed is tapped by a secret agency and ordered to betray Archer. Trip transfers to the Columbia.
While attending a conference on a proposed interplanetary alliance, Trip and T'Pol find out from a dying woman that they have a baby. Investigation shows the woman was a member of the xenophobic organization Terra Prime.