After the events of Raven's Gate, Matt goes to a new school which the Nexus are paying for, but is left friendless because of a bully named Gavin Taylor, causing Matt to injure Taylor by using his powers. Susan Ashwood and Fabian, members of the Nexus, ask him to help them acquire an old diary which could enable them to stop a second gate being opened. He refuses. Meanwhile, Gwendolyn, his aunt, has fallen under the influence of dark forces. She kills her spouse Brian, steals a petrol tanker, and drives it into Matt's new school in a desperate attempt to kill him. Fortunately, he uses his clairvoyance powers and manages to evacuate the whole school before it happens. Matt realizes that he must stop the gate from being opened and agrees to meet the bookseller, Morton, at St Meredithe's Church after a meeting with the Nexus. Morton affirms him to be one of the Five, but he is killed in the process and the diary is stolen by Diego Salamanda, another bidder who wants to use the diary to open the second gate. The Nexus persuade Matt and his carer, Richard Cole, to fly to Peru, find the second gate, and stay at a house belonging to Fabian. However, on their way to the planned rendezvous, the Hotel Europa, the car is ambushed and Richard is kidnapped but Matt manages to escape.
With the help of a local Peruvian, Pedro, Matt manages to get to the meeting place but is captured by the Peruvian police at the hotel, led by the sadistic Captain Rodriguez, and brutally beaten. Pedro saves him. Then, they escape to the Poison Town, where Pedro lives. Strangely while all the town is affected by diseases, the street in where Pedro lives in seems unaffected. Here, they meet the man Sebastian (who can speak English, unlike Pedro), who agrees to help Matt. As night passes, Matt meets Pedro in a dream, revealing that he is one of the Five. Matt finds the markings of his previous beatings have all gone. Thinking Salamanda had Richard kidnapped, Matt and Pedro travel to his hacienda in Inca, but they are discovered. Salamanda reveals that he does not have Richard. An Inca, Micos, one of Richard's kidnappers, helps them escape, and he is killed in the process. He tells them to travel to Cuzco before he dies, and there, Matt manages to contact Fabian and the Nexus on their whereabouts. However, Rodriguez and the police arrive but Matt and Pedro escape with the help of several Incas, led by Atoc, Micos' brother. Then they are taken to the Mountain of the Sleeping God Mandingo. From there, they descend into the town of the last Incas, Vilcabamba, where Richard, having been staying there after being separated, is waiting for them. There, Richard reveals that the kidnapping was conducted to prevent Matt from reaching the Hotel Europa. Based on the Salamanda's knowledge of their movements, Matt and Richard deduce that there is a traitor in the Nexus tipping him off. At the village, it is learned that the gate is located somewhere in the Nazca Desert. They travel to the Nazca Desert with Professor Chambers, an expert on everything Peruvian, and Matt realizes that the Nazca lines are the second gate. The gate will only open once all the stars align with each of the drawings, however, the gate has been constructed such that the stars will never all align at once, and in this case, the star Cygnus is not in its proper position. However, Salamanda has sent a satellite as a substitute star, an evil star, to open the gate. Matt and Pedro break into Salamanda's headquarters with some help of the Incas in an attempt to stop his plan by destroying the radio mast controlling the satellite. At the control center, it is revealed that Fabian is the traitor in the Nexus, having believed it was pointless to try and stop the opening of the gate. Rodriguez then bursts into the room and shoots Fabian when he tries to stop Matt and Richard from being killed. The radio mast is destroyed and falls into the building, flattening Rodriguez. In his dying moments, Fabian reveals that Salamanda had taken control of the satellite once it was in range, using a different satellite dish out in the desert. Atoc takes Matt and Pedro on a helicopter to the dish, but the helicopter crashes, killing Atoc and breaking Pedro's ankle. Matt has no choice but to stop the gate from being opened alone. He manages to trigger his power, destroying the dish and trailer Salamanda is using, and kills Salamanda when he shoots at Matt by deflecting two bullets back to him. However, the satellite is revealed to still be continuing on its trajectory, opening the gate. The Nazca lines crack open and an army of demons arise, before the King of the Old Ones himself appears, and challenges Matt. Matt uses his powers to wound them but he over-exerts himself and falls into a coma. The Old Ones, biding their time, temporarily hide from the world.
Matt is taken to Professor Chambers' house and a doctor examines Matt but does not think he will survive. But Pedro comes back from hospital early and insists on being alone with Matt. At this point, Pedro's power is revealed to be the power to heal. This explains the reason why the street Pedro lived in was the only place in in Poison Town that was unaffected by disease. Matt awakes from his coma thanks to Pedro and decides that the only way they can defeat the Old Ones is to find the other three Gatekeepers.