This is the fourth book in the Gatekeepers quintet, and is the darkest in the series so far.
The first half of the book felt a little disjointed, so it started with what felt like a mini-story about Scarlett, the new character introduced at the end of the third book, Nightrise; the book gives us her background - similar to Matt, she was fostered, and in a flashback the book tells of how she was saved from being run down on the road by a mysterious stranger.
Like the other characters in the series, she has dreams about the other four gatekeepers, so when she has a vision (it seems) of Matt in a church while on a school trip, she recognises him. She follows Matt through a door, which turns out to be one of the portals featured in the previous two books, but she finds herself being held prisoner in an Eastern European monastry. This story is resolved quicky, and the narrative then cuts to Matt's story, picking up from the endings of Evil Star and Nightrise as Matt, Pedro, Jamie and Scott are approached by someone who can offer them the diary that was mentioned in previous titles; typical to the series, as soon as he gives them the diary, he is killed, and this is followed with a battle with the "old ones", the monsters trying to end the world.
The main plot of the story, in which Scarlett is tricked into going to Hong Kong (she is told her father wants her to go there) starts about half way through the book, and the story gets better, and creepier. Scarlett is given a creepy guardian, who seems similar to Jane Deverill from Raven's Gate (so I could guess this was not good); I noticed she had some scary powers of persuasion which she used on the man accompanying Scarlett in the airport after he became suspicious.
Hong Kong, as portrayed in the book, is definitely not as it is in real life, as it seems that the Old Ones have turned it into something reminiscent of Invasion of the Body Snatchers, and the plan seems to be to ensure that Scarlett doesn't leave.
The only real problem towards the end of the book was that there seemed to be an endless cylce of a character getting rescued, running from enemies and then getting captured again, but the finale was worth waiting for, and very shocking. It ended up on a cliffanger that looks like a good setup for the final book, Oblivion, which I'm looking forward to reading.
I am not even sure if Scarlett will survive to see the start of the final book though; at the end of this book she was shot in the head, but it was not definite that she died or not. My suspicion is that she will die and be replaced by the past version of her, Scar, seen in Nightrise, just like Jamie was thrust into the past after the original version of him died.
Next book: How to Remember Everything (Richard Wiseman)