The Four-Year-Old, an extraordinary killer, has arrived in London, hell-bent on destruction… PI Joel Sorrell is approached by the mysterious Kara Geenan, who is desperate to find her missing brother. Joel takes on the case but almost immediately, an attempt is made on his life. The body count increases. And then Kara vanishes too… as those close to Joel are sucked into his nightmare, he realizes he must track down the killer if he is to halt a grisly masterplan – even if it means sacrificing his own life.