Commander William Riker of the Enterprise-D is torn between his loyalty to Captain Picard and his duty to a former captain. To shed some light on his predicament, Riker visits a holodeck recreation of the final mission of the NX-01 and signing of the Federation Charter.
A human isolationist leader threatens to destroy Starfleet Command unless all aliens leave Earth immediately.
A xenophobic faction of humanity threatens to undermine talks to form a new coalition of planets.
In the mirror universe, Archer commandeers the 23rd-century Defiant from the Tholians and uses it in a nefarious power grab.
In the mirror universe, Commander Archer mutinies against Captain Forrest in order to capture a future Earth ship found in Tholian space.
As a gift for negotiating with the Orion Syndicate, Captain Archer receives three Orion Slave Girls. Soon, their seductive powers begin to affect everyone on board except for Trip and T'Pol.
With Columbia's help, Enterprise's crew grapples with sabotage to their ship as they pursue the truth behind the kidnapping of Phlox.
While Enterprise visits Earth for the launch of Columbia, Phlox is kidnapped and forced to help the Klingons deal with a grave threat to their species.
Archer visits Shran's icy homeworld to find an Andorian subspecies called the Aenar, to determine their connection to the marauder destroying ships in the region.
Archer tries to unify the Andorians, Tellarites and Vulcans in a plan to capture a marauder ship threatening to destabilize the region.
Enterprise journeys to Babel with a Tellarite ambassador on board for peace talks with the Andorians, when a distress call from Shran is received.
Non-corporeal aliens study the Enterprise crew as they respond to a fatal viral infection brought on board from an away mission.
The inventor of the transporter, Emory Erickson, comes aboard Enterprise for a risky experiment.
Archer, T'Pol and T'Pau attempt to take a sacred, but controversial artefact back to the Vulcan High Council, in hopes of settling an internal struggle going on among the Vulcan people. Meanwhile, Trip and Soval take Enterprise to Andoria to convince Shran to help them stop a war.
Archer and T'Pol locate the Syrrannites. However, unbeknownst to Archer and T'Pol, more is going on than just a simple act of terrorism.
Earth's embassy on Vulcan is bombed and the evidence points to a religious faction known as "Syrrannites", a group following a revolutionary interpretation of the teachings of Surak, the father of Vulcan logic. After T'Pol receives a clandestine lead, she and Archer embark upon a treacherous journey through the Vulcan desert looking for them.
After turning on their creator, the Augments attempt to start a war between Humans and Klingons.
Soong returns to Cold Station 12 with the Augments, a medical facility where he once worked, where there are hundreds of genetically engineered human embryos stored.
Criminal Arik Soong is brought aboard Enterprise to assist in finding some genetically enhanced humans he created after stealing altered DNA left over from the Eugenics Wars.
Enterprise returns to Earth to a hero's welcome, Archer is haunted by his experiences and actions in the Expanse. Meanwhile, realising that his home has been destroyed, Trip travels to Vulcan with T'Pol, where she faces a difficult situation.
With Silik's help, Archer searches for the temporal operative who altered Earth's past and threatens to destroy all of time.
Archer and the crew of Enterprise find themselves in 1944 and discover the outcome of World War II was altered by the Temporal Cold War.
