After a devastating attack on Earth kills seven million people, Captain Archer and the crew of the NX-01 venture into the Delphic Expanse to seek out those responsible.
On a mission to investigate an abandoned Xindi vessel on a jungle planet, Archer, Reed and Hoshi succumb to a virus that mutates them into a primal life form.
When Enterprise responds to a distress call from a Vulcan ship stranded in the Delphic Expanse, Archer and his boarding team are attacked by insane zombie-like Vulcans.
Archer, Reed and Major Hayes infiltrate a Xindi-Sloth industrial colony to learn more about the weapon of mass destruction that will be used against Earth.
A spatial distortion leaves Archer unable to form any new long-term memories. Years in the future, he wakes up one morning and is stunned to learn the outcome of the human-Xindi conflict.
When a settlement of humans living a 19th-century Western lifestyle is discovered on a Delphic Expanse planet, Archer and crew set out to learn how they got there.
When Trip suffers a catastrophic injury, his only hope for survival is a transplant from a "mimetic symbiont" which Phlox grows from one of his exotic creatures.
The fate of Enterprise is in Dr. Phlox's hands as the rest of the crew must be induced into a coma in order to survive a trans-dimensional disturbance.
Two high-ranking Xindi offer to stop the launch of their superweapon if Archer can prove they've been manipulated. Meanwhile, the crew mourns their lost mates.