Kat Cross and the Case of the Calendar Killer

It all happened in the same chilly January evening -- eight murders, each one hundreds of miles from the next -- and yet, somehow, they were connected. To make matters worse, the killer has left a message: they're going to strike again, and it's going to make their last killing spree look like child's play, by comparison. It's just strange enough to make one so-called Katherine Cross, once an amateur detective, worm her way out of hiding.

When the elusive Ace, supposed "undefeated expert detective" and the bane of Kat's existence, announces to the world that they are on the case, the last thing Kat could have predicted would be teaming up with the infuriating detective who hides behind a screen.

Will Kat solve the case before the Calendar Killer strikes again? Why does Ace want to work with her, of all people? What does this all have to do with the death of her childhood friend, years ago?