The Girl in the Pool (2024) on Netflix

Plot summary

Thomas lives in a suburban house with Kristen, his wife, and their grown children, Alex and Rose. With the family out, he invites Hannah, a woman much younger than he is, to the house on his birthday. They are at the pool when a neighbor's drone passes overhead and takes his attention. Hannah is floating in the water, lifeless. He lifts her out and puts her in a storage bin beside the deck. Kristen and the children come home soon after to throw him a surprise party, and the guests gather, among them his father-in-law William and Kevin, Hannah's husband. Thomas tries to keep his composure through the celebration while keeping what is in the bin out of sight.