It was nothing Petra would have ever noticed, even if it had stared her in the face. And her initial reaction is big deal. A year after the Cold Heart murders and Detective Petra Connor is, once again, working Hollywood Homicide solo. She's struggling with a baffling drive-past murder when Isaac Gomez appears in her office to tell her he's found something she might want to take a look at. Isaac, a twenty-two-year-old prodigy researching crime patterns for his thesis, has been assigned to Petra's care, and she views him with a mixture of protectiveness and irritation. His idea that there's a connection between six unsolved murders committed in the LAPD area over the past six years, all at around midnight on June 28, seems fanciful at first - but as Petra starts to look closely at the files, the links become more and more clear. Something evil has managed to conceal itself between the dry pages: a series of killings so meticulously constructed that the mind behind them would have remained invisible without Isaac's sharp probing. And June 28 is just a month away - will Petra be able to stop the murderer from striking again?