A killer the police have dubbed Billy Dead Mates is killing pairs of best friends one by one. Just before each murder he sends his victim a small white book...Three regional police forces are working together to catch Billy. Then a fifth victim scared by what she's seen and heard on the news comes forward. Stand-up comedian Kim Tribbeck has one of Billy's books. A stranger gave it to her after a gig she did a year ago. Now Kim's life depends on working out why she - a woman who has no close friends - should attract the attention of the Best Friends Killer... And if Billy has her in his sights why has he waited so long to strike?