4-01: Storm Front, Part I

Trapped in Earth during World War II, Enterprise investigates dramatic changes in the timeline as a result of the Temporal Cold War.

4-03: Home

As the Enterprise crew unwinds following the completion of their stressful Xindi mission. T’Pol and Trip visit Vulcan where she grapples with making a difficult decision.

4-04: Borderland

Archer recruits Dr. Arik Soong from prison to track down a genetically-engineered group of radicals, whom he raised as children.

4-05: Cold Station 12

The Augments attempt to steal the remaining genetically-engineered embryos from Cold Station 12.

4-06: The Augments

After turning against him, Dr. Soong assists Enterprise track down the Augments.

4-07: The Forge

After a terrorist attack on Vulcan kills Admiral Forest, an investigation leads Enterprise to believe that an secluded group called the Syrrannites is responsible.

4-08: Awakening

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.

4-09: Kir’Shara

Tensions mount as different Vulcan factions fight for control of the Kir'Shara.

4-10: Daedalus

The Enterprise assists Emory Erickson, the inventory of the transporter, who is secretly trying to save his long-lost son.

4-11: Observer Effect

With Hoshi and Trip suffering from a fatal illness, Organians study the Enterprise crew.

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.

4-13: United

While investigating recent attacks, Archer mediates a quarrel between Shran and Ambassador Gral.

4-14: The Aenar

Archer and Shran seek out the Aenar, an Andorian subspecies, to investigate their connection with recent attacks.

4-15: Affliction

Phlox is abducted by Klingons and forced to find a cure to a fast-spreading illness. Meanwhile, Section 31 reaches out to Reed.

4-16: Divergence

As Enterprise investigates sabotage, the crew continues their search for Dr. Phlox.

4-17: Bound

Orion slave girls come aboard Enterprise and disrupt the ship’s crew.

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.

4-20: Demons

A fanatical group of xenophobes attempt to rid Earth of all non-humans and end all extraterrestrial relations.

4-21: Terra Prime

With the threat of destroying Starfleet Command, Enterprise races to stop Paxton.