'K, so Vulcan ship lands, probably in footage nicked from First Contact, Vulcan comes out and is promptly shot by Zephram Cochrane. Because this is the EEEEEEEVIL MIRROR UNIVERSE! Hey, that's a better title sequence than the regular one.
Ah, Phlox and Reed have invented the agony booth, and they're torturing a Tellerite with it. Forrest is in command of the Evil!Enterprise, and Hoshi is... um... his concubine, by the looks. Apparently the war is not going well, with a defeat at Tau Ceti.
Archer decides to take over the ship and has Forrest chucked in the brig so he can go off to Tholian space on some mission he's come up with.
So seeing as this is an alternate universe, it's somewhat coincidental that T'Pol's ended up on board anyway.
Archer sends her down to engineering to help Trip install a Suliban cloaking device. Then there's some crew bickering and stuff. Hoshi tries to stab Archer unsuccessfully at one point.
They locate a Tholian ship and disable it. They beam the pilot aboard before the other ship explodes.
Archer interrogates the Tholian to try and get the location of a captured Terran ship. After some torture, it complies and they set course. The cloak breaks after an EPS overload, which leads to Trip being put in the agony booth while Archer goes and sexes Hoshi.
T'Pol and a couple of other Vulcans free Forrest and they go to retake the ship. They take over the bridge, only to find they can't steer the ship - Archer says the autonavigation won't release until they get to the co-ordinates he set. They stick him in the agony booth for a while.
Later on, Forrest releases him because his superiors have approved the mission.
Archer briefs everyone - apparently the Tholians opened a rift to an alternate universe and used a distress call to lure a ship through - a starship from the regular universe, and from 100 years in the future. Archer wants to get it for the technology.
T'Pol admits to Trip that she manipulated him into sabotaging the cloak. They bring the (now fixed) cloaking device online and reach their destination, where the TOS-era starship (the Defiant) is located.
Archer wants to retrieve the ship, but Forrest says to just download the database and destroy it. He also suggests to T'Pol that Archer not return from the mission.
The away team has a look around. The Tholian in decon starts transmitting a distress singal, so Phlox kills it. The nearby Thonlian ships construct a web trapping Enterprise.
Trip powers up the Defiant and they detect Enterprise under attack. Forrest orders abandon ship as the warp core starts overloading and then, as the away team watches from the Defiant, Enterprise explodes. To be continued.
YO! That was a spiffy episode.