The Book of Secrets — Elizabeth Joy Arnold

After more than twenty years of marriage, Chloe Sinclair comes home one night to find that her husband, Nate, is gone. All he has left behind is a cryptic note explaining that he's returned to their childhood town, a place Chloe never wants to see again.

While trying to reach Nate, Chloe stumbles upon a notebook tucked inside his antique copy of The Lion, the Witch and the Wardrobe. Written in code, the pages contain long-buried secrets from their past, and clues to why he went home after all these years. As Chloe struggles to decipher the notebook's hidden messages, she revisits the seminal moments of their youth: the day she met the enigmatic Sinclair children ane the increasingly dangerous games they played to escape their troubled childhoods; the first time Nate kissed her, camped out on the beach like Robinson Crusoe; and the elaborate plan she and Nate devised, inspired by Romeo and Juliet, to break away from his oppressive father. As the reason for Nate's absence comes to light, the truth will forever shatter everything Chloe knows -- about her husband, his family, and herself.