Sarah [Shirley Henderson] and Tom [Alan Tudyk], a British couple, host an intimate dinner with their friends Richard [Rufus Sewell] and Beth [Olivia Williams], while their guest Jessica [Indira Varma], a newly bestselling author, tags along. The evening starts with a brittle tangle of finances, and Sarah’s patience wears thin as Jessica’s flirty, inappropriate humor keeps circling back. The mood tightens as Sarah snaps at Jessica, sending the author off in a huff from the dining room.
When they search for Jessica before dessert, they discover a shock: she has hanged herself in the garden. Tom wants to call the police, but Sarah blocks him, fearing the upheaval it would cause to their looming home sale. She suggests moving Jessica’s body to her own house, a plan they discuss in a fog of fear and pragmatism.
As the group debates what to do, Miranda [Anne Reid], Tom and Sarah’s neighbor, rings the bell hoping for an autograph on her copy of Jessica’s latest book. In a bid to appease her, Sarah forges Jessica’s signature using a credit card found in Jessica’s purse as a reference. The moment exposes a deeper web of manipulation, and Richard pleads with the couple not to lie, only to be met with Sarah’s quiet threat to remind him of a past legal maneuver that helped Tom skirt rules and nearly got him disbarred.
The doorbell rings again, this time with two constables informing them that someone dialed 999 from the address and insisting on an interior search. Beth comes close to telling the truth, but holds back, and the police are sent on their way with a vague sense of suspicion. With the threat of being exposed, Richard panics and—feeling cornered—agrees to go along with the lie, which only fuels Beth’s fury and sparks a heated argument between them.
Tom gets a call from the estate agent: the buyers are set to tour the house that evening. In a panic, they stash Jessica’s body in the toilet and hope the day’s events won’t blow up before the sale is sealed. After the buyers depart, Sarah unloads her anger on Beth for provoking a confrontation with Klaus, the buyer’s husband, who is portrayed as a wealthy oil magnate. Beth, desperate and shaken, proposes a more dangerous bargain: she will help move Jessica’s body if Richard grants her a divorce.
Richard finally crumbles under the strain, unable to assist with repositioning Jessica’s body while it still hangs in her flat. The group pushes through the maneuver, and on the drive home they begin to reckon with what Jessica did and why she chose them to bear the burden of her death. A note from Jessica later surfaces, confessing that she planned to die near her oldest friends and apologizing for dragging them into the mess. Grief sweeps through Sarah, and she contemplates calling the police, triggering yet another round of bickering.
Klaus returns to push the signing of papers, and Sarah, still conflicted, refuses to let the matter rest. After a tense standoff, Tom distracts the authorities by claiming he inspired the adulterous character in Jessica’s book, and the police opt not to file a report once he serves them some of his clafoutis. Klaus signs the papers, and Beth and Richard head home with a restrained but hopeful farewell.
In the final twist, Tom and Sarah reconcile over dessert, and their young adult daughter arrives home for the night, adding a glimmer of normalcy to an evening that began with a haunting crime. Sarah closes with a quiet, hard-won optimism: Jessica was right about one thing—that they were, in a strange way, lucky to still be standing together.
