Upon returning to the Xindi weapon test site, the crew of Enterprise detects a Xindi ship in the area. They attack and board the ship, taking its occupants prisoner. Among the prisoners is Degra, the Xindi-Humanoid who is also the mastermind behind the superweapon. Unfortunately, the Xindi ship's databanks have been mostly erased and Degra and his men are less than helpful. Phlox, however, has discovered an interesting wrinkle in Xindi neurophysiology — it's possible to erase their most recent memories. Archer formulates a plan that involves Phlox erasing Degra's memories and Trip building a small mock shuttlecraft that will be housed on Enterprise.

When Degra awakens onboard the mock shuttlecraft, Archer tricks him into believing that the two men shared a cell in a Xindi-Insectoid prison for the last three years and have recently escaped. Archer explains that the Xindi were successful in deploying their weapon and destroying Earth, but the victory only led to infighting amongst the various Xindi species. The Insectoids attacked the other Xindi colonies and killed thousands of Degra's people. Degra is suspicious of Archer's assertions, but as the two men spend more time together, he has no choice but to believe the captain. Archer seems to be aware of many personal details of Degra's life, including the names of his wife and children. Of course, the whole thing is a ruse — Archer knows these details because some of Degra's personal information was still available in the Xindi ship's database. He continues to try and win the Xindi's trust, hoping that Degra will reveal the location of the superweapon.

Thanks to further subterfuge from the Enterprise crew, Degra comes to believe that his family is still alive and located at the colony of Azati Prime. Archer suspects that Azati Prime may be the location of the weapon. He finally convinces Degra to enter the coordinates into the mock shuttle's computer. Degra, however, seems to be growing more suspicious of Archer. When Archer can't answer a personal question about Degra, the Xindi realizes that he must be part of a set-up and attacks the captain. Trip, Mayweather and the MACOs storm the mock shuttle and drag Degra back to the brig.

Now that he knows he's been tricked, Degra tries to convince Archer that Azati Prime is not, in fact, the location of the weapon. Archer is unsure, so he stages yet another ruse, and tricks Degra into thinking that Enterprise has already arrived at Azati Prime. A desperate Degra blurts out that the ship will never get past the Xindi defense perimeter — just the confirmation that Archer was looking for. Confident that the superweapon is located on Azati Prime, Archer has Phlox wipe Degra's memory clean once again, so the Xindi will not remember his encounter with Enterprise. After returning an unconscious Degra and his men to their ship, Archer sets a course for Azati Prime, hopeful that this will be the last phase of Enterprise's quest for the Xindi weapon.