After packages boobytrapped with a substance that activates nanites are sent to dozens of powerful people around the world, briefly turning them into rampaging E.V.O.s, White Knight dispatches a team made up of Rex, Agent Six, Bobo Haha, and Dr. Holiday to the Amazon to secure an abandoned base to which the packages have been traced. The base is where a missing scientist named Gabriel Rylander is thought to be hiding; the team is to apprehend him and secure his research, keeping it from falling to the Pack, which is also en route. The voyage is eventful and dangerous, with the team traveling at first by riverboat and encountering a swarm of piranha-like E.V.O., and later overland, contending with Rylander’s automated defenses and sentry robots. Meanwhile, the Pack (now including a Jungle Cat E.V.O. member following Breach’s presumed death) is led through the forest by Van Kleiss, wearing a special soil-circulating suit to maintain his powers. After the Jungle Cat E.V.O. accidentally ruptures the suit during a skirmish with Rylander’s sentry robots, Van Kleiss drains his nanites, petrifying him. The two expeditions locate the base at the same time, and a battle ensues. After Providence air support arrives, White Knight orders them to abandon retrieval and simply bomb the building to deny it to Van Kleiss. With the rest of the team fighting the Pack outside, Rex enters the base and finds Rylander, who surprisingly recognizes Rex. The somewhat unstable, rambling Rylander gives Rex a fragmentary account of his past before injecting him with a syringe containing a single large, abnormal-looking nanite. Van Kleiss unexpectedly arrives and injures Rylander before he is able to answer any more of Rex’s urgent questions. Van Kleiss and Rex fight, but when Rex cuts off Van Kleiss’s mechanical left hand he uses his powers to gain the upper hand. Before he could finish Rex off, the injured Rylander lunges at Van Kleiss. The two are thrown into the aperture of a reactor vessel, where both are to all appearances vaporized. Rex is found by Six and escorted out of the disintegrating building, and the Providence task force retreats by air as the base goes up in a mushroom cloud. Rex tells Agent Six and Dr. Holiday that he learned from Rylander that he has a brother.