Enterprise follows a lead and discovers a Xindi lab that refines Kemocite, the key ingredient in the weapon being built to destroy Earth. An away team of Archer, Reed and Hayes confront the lead researcher, Gralik Durr, who was employed by Degra to refine the Kemocite but was never told what it would be used for. When Gralik realizes it was his research that contributed to the 7 million deaths on Earth, he agrees to help Archer prevent further loss of life. Meanwhile, on Enterprise, Phlox and Tucker study the weapon they seized from the Xindi and find an organic component, a life-form serving as the rifle's power cell. Despite T'Pol's objection, Tucker tests the weapon.