Cheating with my Step-SisterStepsister arrives for a month with one towel and one secret

The story

Breaking news from a cramped apartment. Quinn turns up at her stepbrother's place with a hello, a suitcase and a plan to stay for the month, courtesy of Dad. His girlfriend is in the next room, and Quinn, towel in hand, heads straight for the shower. He tells his girlfriend that this is his stepsister and promises to speak with her about the towel. Inwardly he admits he wants her badly. Quinn remarks that he looks happy to see her. The girlfriend is twenty feet away.

The twist

The second episode has Quinn teasing him about what is under her towel. He tells her he has a girlfriend now. She tells him she misses being his dirty secret, and suggests the girlfriend could join. He is cornered.

Developing story

Beyond the free pair, the girlfriend remains in the next room and the secret remains in the middle. A month is a very long time.