An extraordinary killer, the Four-Year-Old, has arrived in London, and is hell-bent on destruction. No sooner has PI Joel Sorrell been approached by the mysterious Kara Geenan, who is desperate to find her missing brother, than an attempt is made on his life. When Kara vanishes too, it becomes clear that this is no routine job. Something is casting a long, long shadow over the case, and Joel must travel north, to a past he was desperate to forget, in order to find out the truth. As those close to Joel are sucked into his nightmare, he knows he must track down the killer fast if he is to halt a grisly master plan - even if it means sacrificing his own life.