King manages to pull off something that looked a bit dodgy when it first became manifest in Finders Keepers -- namely, the introduction of the paranormal into the world of Bill Hodges. Brady Hartsfield, the Mercedes Killer of the first Hodges novel, was left with a brain made of mush at the climax of Mr. Mercedes. Hodges' soon-to-be-partner-in-private-detection, Holly Gibney, bonked Hartsfield on the head just before he could blow up an auditorium filled with thousands of boy-band-loving teenagers.
However, experimental drugs and the vagaries of the brain have slowly granted Hartsfield mental powers. He fakes being non compos mentis to avoid prosecution for his crimes while he gains strength and lethality.
Hartsfield is a return to one of King's favourite types, the Outsider with Wild Talents. Unfortunately, this psychic wants to kill people -- as many of them as possible. King combines a quasi-scientific mind-control premise that stretches back to at least Arthur Conan Doyle's "The Parasite" with an antagonist who's one of Thomas Harris' serial-killing grotesques writ larger and with super-powers.
Brady Hartsfield doesn't just want to kill people -- he wants to find ways to trick them into killing themselves. And with his powers, he now can. King's heroes have to engage Hartsfield on multiple fronts to stop him, from the Internet to the real world to the nebulous world of the mind.
Somehow, it all works. Even the bit where a character survives a gunshot because of something in her pocket. Well, OK, that doesn't quite work.
Otherwise, End of Watch works in part because Bill Hodges and Holly Gibney are carefully drawn characters. Hartsfield is a terrible, pitiful antagonist. There's also an immensely clever plot device involving video games and hypnotism. And there's a snowstormy climax that recalls the closing chapters of The Shining. In terms of tension and pleasure of reading, Mr. Mercedes remains the best of the Hodges trilogy, but End of Watch runs a close second. Highly recommended.