4-12: Babel One
While transporting a Tellarite ambassador, Enterprise rescues the crew of Shran’s ship and becomes caught up in a dispute between the Tellarites and Andorians.
Archer recruits Dr. Arik Soong from prison to track down a genetically-engineered group of radicals, whom he raised as children.
T’Pau and T'Pol's mother, both Syrrannites, assist Archer and T’Pol search for the Kir'Shara and uncover the truth behind the terrorist attack.
4-18: In a Mirror, Darkly
In the mirror universe, a radically different Enterprise crew searches for the technologically-superior U.S.S Defiant, trapped from our universe.