Teenage Sonny Cooke (Sam Nivola) has a close relationship with his single mother Ellen (Connie Britton), who he considers one of his favourite people in the world. The pair have a secret code - squeezing each other's shoulders - to say they love each other. Sonny is involved in a terrifying car accident that almost takes his life and he wakes to find his mother is somehow changed. The teenager is convinced that Ellen has been replaced by a doppelganger and he teams up with his friends Mallory (Grace Brennan), Vogel (Maliq Johnson) and Weldon (Colter Lee) to prove his wacky theory in an eight-part mystery created by Nick Paley.