PART THREE — Saturday, 20 July

After Josie leaves, Alix immediately feels the house become lighter and more normal. Alix reassures Nathan and Leon that Josie will be fine with her mother, though Alix privately doubts Josie is really going there. While preparing rooms for her sisters and their children, Alix strips Josie’s bed, checks the room, and finds that Josie has left the key marked number 6 hidden under the mattress. Alix senses the key may have been left deliberately and keeps it.

Zoe, Maxine, and their children arrive, and the house fills with family noise, paddling pools, drinks, pizza, and summer heat. Nathan joins briefly, pacing his drinking and appearing determined to keep his promise to Alix that he will return before midnight. Before Nathan leaves to meet friends, Alix tries to make the promise playful and intimate, and Nathan swears he will behave.

At 7:30 p.m., Josie secretly follows Nathan to the Lamb & Flag, disguised in a new dress, straw hat, and red lipstick. Josie overhears Nathan tell his friends that he is celebrating the departure of the houseguest from hell, describing Josie as a freak who made him uncomfortable in his own home. Josie is hurt but not surprised, and Nathan’s contempt strengthens Josie’s resolve to continue with her plan.

Josie texts a young woman named Katelyn, directing Katelyn to Nathan’s table. Katelyn joins the men under the pretense of waiting for a friend, then says she has been stood up and asks to stay with the group. Nathan and his friends are visibly flattered by Katelyn’s attention, and Josie watches with satisfaction before leaving the restaurant.

Meanwhile, Alix spends the evening with her sisters but grows increasingly anxious when Nathan does not respond to her message and stays out later than expected. Just before midnight, Alix discovers a plastic bag with white powder residue, a hotel key-card holder from the Railings, and a napkin bearing the name Daisy in her shoe rack. Alix believes the items point to one of Nathan’s recent lost nights, but she decides to handle the discovery calmly rather than expose it to her sisters. When Alix calls Nathan after midnight, the call rings out.

At 12:30 a.m., the perspective returns to Josie, who reveals that she planted the items in Alix’s shoe rack before leaving. Josie imagines Alix discovering them and Nathan ignoring Alix’s call while partying with Katelyn. When Katelyn texts that she and the men are going inside, Josie replies that she is on her way.