Step-Sister's SecretTherapist's couch hears everything as stepsisters share more than a car

The story

She booked a therapist to get a man out of her head. He happens to be engaged to her stepsister. Session one is all confession: a scenic drive through the pines, a fiance lent out like a rental car, and a stepsister who declares that sharing is the family rule. Cars, roads, anything that fits. The tension builds with every bend. By the end of the hour, the woman on the couch is not sure whether she is being cured or cast in somebody else's script. Insiders at the clinic say the plot thickens.

The twist

Episode 2 rewinds to a foggy bathroom, a door left slightly open and a question about her that nobody answered with a no. The therapist urges her to start from the dark, and the stepsister walks in with a smile.

Developing story

Everyone in that family, therapist included, may be writing the same script. The paid episodes reveal who is steering this story.