What is the Lying game about?

It's about Emma Becker who is a foster kid, she finds her twin sister Sutton Mercer who lives "the sweet life" in Phoenix. They find each other because Sutton is searching for her birth mother an finds Emma.
When Emma is framed by her foster brother she runs to Phoenix to her twin and they switch places because Sutton has a led on their birth mother, so Emma will be in Phoenix pretending to be Sutton.

That's the main thing in the series, so far 9 episodes and next is Fall finally.
Hope it helped you out =)