Matt was first seen in Necropolis, when he was reading a newspaper article about a girl called Scarlett Adams who had been missing for a day after walking through a door in Saint Meredith's Church in London, England. This is the same Church and door that Matt walked through in Evil Star, and as only the five Gatekeepers can travel through that door (with one companion each), and 24 other doors around the world that take them around the world. Matt knows that Scarlett is the fifth and final Gatekeeper.
Matt has now turned fifteen years old and is still living with Joanna Chambers, Richard Cole, Jamie & Scott Tyler and Pedro in Peru. Now that he knows Scarlett is in London he sets out to find her with Jamie and Richard, leaving Scott and Pedro back in Peru. However before this happens and whilst Matt and the others are still in Peru, they are visited by a man named Ramon who claims to have worked for Salamanda before, but know nothing about him working for the Old Ones. Ramon also brought St Joseph of Cordoba's diary which contains information that the Gatekeepers need about the doors, Old Ones and the gates. Then zombies attack the house, killing Ramon, attacking the first four Gatekeepers, the professor and Richard and setting the house on fire. Later Professor Chambers dies because of the attack and Matt, Jamie and Richard finally go to London to find Scarlett. Pedro and Scott go back to Vilcabamba to stay safe.
They arrive to find out by Scarlett's housekeeper that Scarlett's father has rushed her to Hong Kong on apparent "urgent business". Matt is very disappointed by this news and he, Jamie and Richard have a meeting with The Nexus where Matt finally discovers the Old Ones' plan. The Old Ones have trapped Scarlett in Hong Kong, China in hope of luring Matt there too by using Scarlett as the bait. It is then discovered that the Old Ones want the Gatekeepers to have the diary, so that they can discover where the doors around the world are, and as there is one in Hong Kong the Old Ones hope the Gatekeepers will go through the door where the Old Ones will capture them all and torture them, whilst the Old Ones take over the world. It is then revealed that Scarlett's father works for Nightrise and so will give Scarlett to the Old Ones.
With no other choice Matt, Richard and Jamie head to Hong Kong to rescue Scarlett but not via the door as a member of the Nexus reveals he has a friend in Macau who can take them to Hong Kong via boat. When Matt, Jamie and Richard arrive in Hong Kong they are separated when the Nightrise corporation attack the boat they are in. Matt is forced to walk the streets alone, in the streets is a thick smog that smothers Hong Kong and suffocates its residents, later killing them. This is the Old One's plan to turn Hong Kong into a necropolis, a city of the dead. Matt sees people dead or dying on Hong Kong's streets. He even sees some of the creatures that broke out of the Nazca Lines such as a horse with a knife struck through its head like an evil unicorn.
Matt then remembers what the Nexus told him about where Scarlett's father lives, an apartment building called Wisdom Court and decides to visit him. Matt discovers that Scarlett's father, Paul, is worried sick about Scarlett. The next morning The Chairman of the Nightrise corporation kills Paul and captures Matt and takes him to where Scarlett is being held hostage: Victoria Prison. The pair meet and exchange stories whilst a heavy storm begins in Hong Kong, but it is no coincidence. Scarlett's power is to control the weather and she has accidentally caused a huge typhoon in Hong Kong. Lohan Shan-tung (a Triad gangster sent to help Scarlett), Richard, Jamie and two of Lohan's men break Scarlett and Matt out of the prison they are being held captive in. Matt and Scarlett then discover the typhoon which is destroying Hong Kong.
Scarlett then manages to protect her and the others with her powers and they finally reach a temple with the magic door in, which can take them safely back to Peru and the five can be re-united. The temple is protected from the typhoon whilst Scarlett is inside. As they reach the door, Scarlett is shot by a Nightrise agent, leading the temple to collapse because Scarlett can't protect it from the typhoon while she's unconscious. Scott and Jamie rush through at the last minute. The Gatekeepers, Richard and Lohan (Scarlett in Richard's arms) dash through the door before they are killed by the storm.
It is then revealed that as the Gatekeepers had no decided destination they have all been scattered all over the world. It is also revealed that Hong Kong has been completely destroyed by the typhoon but the smog was wiped away. Necropolis then ends leaving readers on a cliffhanger.
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