Paul Finch, the no.1 bestselling author of Hunted and Stalkers, has written an even darker thriller. PC Lucy Clayburn has to delve into the criminal underworld to track down a brutal serial killer, but she's about to discover that going undercover is the most dangerous work there is.
Apply to win one of 50 free copies now. This giveaway ends on 27 September.
We ask all winners to share their thoughts about the book on this discussion thread. However, you don't have to win a free copy to take part in the discussion - anyone who has read Strangers can post their feedback.
Everyone who posts their feedback on the book by 25 November will be entered into a prize draw to win a £100 Love2shop voucher.
This giveaway is sponsored by Harper Collins