Who do you trust when you can no longer trust your own mind?

Emma's life has always been a struggle, and now she's been accepted at a prestigious music school, she is determined to excel. But when the impossibly chic twins, confident Sophie and quieter Matilde, come crashing into her life - surrounding her with champagne and parties - they demand Emma's full attention.

Then shy Matilde commits suicide and shockingly, her identical twin Sophie flourishes. Now odd things are happening to Emma: blackouts, waking up in strange places, bizarre dreams. Something, or someone, is consuming Emma's mind. Terrified, Emma begins to doubt everything and everyone around her, especially the beautiful Sophie...