Detective Cassie Maddox is still trying to deal with the events of In the Woods. She is out of the Murder Squad and has started a relationship with fellow detective Sam O'Neill but is too badly shaken to commit to Sam or to her career. Then Sam is allocated a new case, that of a young woman stabbed to death just outside Dublin. He calls Cassie to the murder scene and she finds the victim is strangely familiar. In fact, she is Cassie's double. Not only that, but her ID says she is Lexie Madison the identity Cassie used, years ago, as an undercover detective. With no leads, no suspects and no clues, Cassie's old undercover boss spots the opportunity of a lifetime: to send Cassie undercover in the dead girl's place. She could pick up information the police would never hear and tempt the killer to finish the job. So Cassie moves into Whitethorn House, poses as a post-grad student, and prepares to enter Lexie's world.

塔娜‧法蘭奇，愛爾蘭知名小說傢。從小由於父親工作的關係，遷徙過多個國傢，直到1990年纔定居都柏林。因為經常搬傢，接觸不同文化，使得她的觀察力也遠比一般人敏銳。

她在都柏林的三一學院接受專業演員訓練，並曾參與戲劇、電影、配音等工作，而這些經曆也幫助她能夠成功模擬角色的各種樣態。其長篇小說處女作《神秘森林》以睿智、細膩、優雅的敘事手法和縴毫畢現的人物刻畫獲得全球各地書評的一緻贊譽，不僅榮獲“愛倫坡奬”、“安東尼奬”、“麥可維提奬”、“巴瑞奬”等四項“年度最佳處女作”大奬，更躍登紐約時報、齣版傢周刊、今日美國報、舊金山紀事報、洛杉磯時報、丹佛郵報、波士頓環球報、Book Sense、北卡獨立書商協會等全美九大暢銷排行榜，並入選亞馬遜網絡書店2007年度編輯推薦選書。此後法蘭奇的第二部小說亦再次席捲國際文壇，並同樣入選亞馬遜網絡書店2008年度編輯推薦選書。