The Lying Game is the first book to The Lying Game series. The story is about a girl named Emma Paxton, who comes to believe she has a twin sister. She goes on Facebook, and sends a message to the girl, Sutton Mercer. Sutton writes back saying that they need to meet. However, Sutton is actually dead. Emma goes to the Sabino Canyon, Tucson, Arizona. While waiting for her sister, she is attacked by a group of people. They take her across the street, and remove the burlap sack over her head. That's when Emma finds out that it's just Sutton's friends playing a prank.
The friends believe that Emma is Sutton, and take her to Nisha's party. Back at Sutton's home, Emma still goes on with the charade as being Sutton, since they are identical twins. The next morning, Sutton's younger sister, Laurel gets a note. She gives the letter to Emma without reading it. The letter says 'Sutton's dead, keep playing along'. Emma is drunk, but goes to the police station, however she is not taken seriously because of Sutton's past lies. When Emma goes to school, Garret, Sutton's boyfriend, takes that Emma is Sutton like everyone else. Emma begins liking a boy named Ethan. Ethan finds out who she really is and is the only one who knows the secret.
Emma learns about a game Sutton and her friends play, "The Lying Game", an elaborate pranking game. Emma also learns that one day that Sutton's friends took TLG too far, and almost strangled Sutton. Ethan told Emma that he saved Sutton that night that she almost died, so Emma concludes that Sutton died after that incident and anyone could have killed her. Emma runs off with Ethan and he finds out that Emma is pretending to be Sutton, but he promises to keep her secret and help her find the killer. Emma decides to stay and pretend to be Sutton so she can find out who killed her sister. Emma returns to Sutton's home, celebrating her and Sutton's birthday. But what Emma doesn't know is that Sutton's murderer is always watching.