Enterprise cruises into range and starts scanning. They see Degra's ship cruise in. Degra and hit pals toast the completion of their superweapon.
Mayweather practices flying the Xndi shuttle they recovered in the previous episode. Hoshi works on insectoid Xindi translation.
Finally, Mayweather and Trip go out in in the shuttle, and have steering problems. When they go in to scan for the weapon, a patrol ship drops by to say hi.
A scanning facility on the moon Enterprise is hiding behind scans Enterprise, and Archer is forced to order it destroyed.
Trip and Mayweather take the shuttle underwater and locate the weapon being constructed. They fly in for a better look.
Back at Enterprise, they look at the scans and work out they can do a suicide mission to blow it the crap up. Archer volunteers. Then, er, Archer finds himself on Enterprise-J(!) and says hi to Daniels and sees soem ships shooting each other outside. Daniels explains that in the future, the Federation fights the Sphere Builders. The Sphere Builders can see the future and warned the Xindi that the humans are a threat. Archer must contact the Xindi and convince them that the humans are not their enemies.
Daniels is unsuccessful in persuading him, and Archer still intends to go on the suicide mission. When Archer is return to his own time, T'Pol says Daniels has a point, but Archer is still not persuaded.
The Xindi get ready for their attack on Earth. Degra is feeling extreme guilt for having created the weapon.
Archer practices piloting the Xindi shuttle, and Mayweather asks why Archer is going on the mission. Archer drops Porthos off with Phlox, then goes and giev his big farewell speech and sods off in the shuttle. T'Pol goes into the ready room and cries for a bit(!!)
Archer finds the superweapon has gone, and is attacked by a couple of insectoid craft.
Trip goes and gives T'Pol a pep talk, and she kicks him out.
The reptilian-Xindi rough Archer up a bit, and he makes fun of them. The Xindi threatens to destroy Enterprise, and Archer says he'll only speak to Degra.
Meanwhile, the Enterprisecrew discuss what to do. T'Pol decides they should wait an hour, and then T'Pol will attempt a diplomatic solution.
Archer talks to Degra about the spheres and how it's the Sphere Makers who will destory the Xindi, and gives him an artifact from the future. Degra talks to some of his fellows.
T'Pol, under Trip's protestations, heads for a shuttle, but then a squad of Xindi ships turn up.
Archer talks to the Xindi some more and asks to talk to the council.
Enterprise is under heavy attack and is disabled.
The reptilian-Xindi chain Archer up again, but Degra and the other Xindi are annoyed because the reptilians are going behind their back, etc.
Enterprise sustains more damage as the Xindi shoot bits off it. Teh end.