Owen and Patty are young and in love. During their honeymoon in Mexico terrible news shatters their happiness. CJ, Patty’s brother, has been senselessly killed in cold blood by a crook. From that moment on, their life goes to pieces, crushed by the weight of the tragedy. Nothing will ever be the same. Patty can think only about her brother’s existence being cut short in that absurd way; and her parents are completely obsessed with keeping the memory of their son alive. Owen’s world sinks into absolute chaos. But he can’t resign himself to the situation; he longs for their lost stability, he wants his Patty and his happy marriage back. He decides he has to do something. It’s a question of justice, the same justice that was betrayed in court. Because C.J.’s murderer, Henry Joseph Raven is not repentant for what he did, never said he was sorry, and the twenty years of prison he is condemned to are not enough for all the pain he has caused. Raven has to suffer like Patty and her family. Raven has to serve a sentence of hell on earth. So Owen, using a false identity, initiates a relationship with the murderer by writing to him in the guise of Lily Hazelton, an anxious and ingenuous young woman. He wants to make him fall in love with “Lily”, only to be abandoned and have his heart broken. But letter after letter, Lily begins to embody Owen’s fantasies, and dangerously takes on the features of his first great love, young Eileen, who died from an overdose. Owen’s waiting for the letters from the prison becomes to seem more and more like a lover’s breathlessly waiting for the answers to love letters. The past and the present, truth and fantasy interweave and blur, taking on fearfully dark contours. Because the obsession for revenge corrodes the mind of the avenger, weaves a dense mass of emotions and sensations that are impossible to escape. This is one of the most famous American first novels of recent years. The Interloper has the suspense of a thriller and a subtle psychological play of identities inserted into a perfect epistolary device that carries the reader to the unimaginable epilogue.