Lady Lucy Endkatell awaits guests for the weekend at her Hollow estate. Among the invitees are the famous doctor John Cristow with his wife Gerda, an absurd and near-by woman, the sculptor Henrietta Savernijk, cousin of Sir Endcatell David, cousin and best friend of Lucy Midge, and cousin of Lucy, writer Edward. Lucy prepared a surprise for the guests - a famous detective will arrive for lunch on Sunday.

Lucy and Midge worry that the party will fail. The absurd Gerda can say something or do something out of place, and John begins to report it. And Edward always feels awkward in the presence of John, believing that he is inferior to everything.

In love with John Henrietta, she dreams that she will spend three days next to him. John once survived an unsuccessful affair with actress Veronica Cray, who preferred him to a career in Hollywood. To console himself, John married Gerda, the exact opposite of Veronica. Now, tired of the sick and unloved wife, John is also waiting for a meeting with Henrietta.

Having met, Edward and Henrietta, recall the time when there was a romantic relationship between them. Loving Edward is ready to renew them, but Henrietta refuses. Edward realizes that Henrietta is in love with John.

Sir Henry, a passionate firearms collector, shoots with John at cardboard targets. Women also try to hit the target, but only Lucy can do it.

Suddenly, Veronica Creil appears in the house. The famous actress lives in a neighboring villa and came to her closest neighbors for matches. Veronica asks John to take her home. Returning, John realizes that Veronica is no longer interested in him. He is ashamed of Gerda, but love for Henrietta is stronger than him.

In the morning, John receives a letter from Veronica in which she asks to come to her. The actress suggests renewing the old relationship. It doesn’t bother her that they have families - lawyers will settle everything. This is why she came to this wilderness, knowing that John often visits his friends. John refuses: he no longer loves Veronica. The actress guesses which of the women present he loves - Henrietta.

On the way home, John decides to start a new life, he will be better off with Gerda, tell her about everything, but then a shot rings out and John falls to the ground.

The famous detective Hercule Poirot, who bought the villa next to the Hollow, comes to the Endcatellas for lunch. A servant leads him to the owners sitting in a small pavilion near the pond. Surprised Poirot sees near the pond John lying and standing next to him, confused Gerda with a gun in his hand. John says "Henrietta" and dies. Also there are Henrietta, in her hands holding a basket full of flowers, and Lady Endcatell, holding a basket of eggs.

Henrietta demands from Gerda that she give up the weapon, but Gerda drops the gun into the pond.

In order not to touch anything before the arrival of the police, everyone gathers in the pavilion. Poirot notices an expensive fur cloak that could not belong to any of the women present, and a box of matches.

Lucy believes Gerda shot John. Henrietta is convinced that Gerda is innocent - she picked up a gun. Gerda denies any guilt, she went to the pond when John lay there wounded. Gerda tells the police inspector that everyone loved John, he was a wonderful husband.

After receiving the results of the examination, the police inspector, together with Poirot, examine the crime scene. Several paths lead to the pond. Lucy came along one of the chicken coops, Henrietta and Edward came along the other two from the forest. The inspector believes that Gerd killed John. She looks silly, but she needs to be followed.

Sir Henry admits that the gun that Gerda threw into the pond was taken from his collection.

Sir Henry takes Gerda home. Edward is trying to calm Henrietta. In love with Edward Midge is jealous. Now that John is gone, Henrietta will marry Edward.A girl works as a saleswoman in a store. She wants to take leave for a funeral, but they don't let her go. A wealthy Edward does not understand why she cannot find another job.

Poirot arrives at Hollow to meet Lucy. On the way, he looks into the pavilion. On the table, the detective notices a painted tree. Lucy incessantly tells him about the life of his butler and about his pity for Gerda. The butler, meanwhile, tells the inspector about Veronica Cray's visit.

The inspector goes to the Kristow family home. John's secretary speaks very contemptuously of Gerd. She does not know about John’s novels on the side, with staff and patients he was always impeccable. The secretary does not believe that Gerda could shoot her husband. The inspector is surprised by Gerda’s behavior, which is indifferent to what is happening, not realizing that she is the main suspect.

The inspector visits Sir Henry. According to the results of the examination, John was not killed from the revolver that Gerda was holding. Sir Henry checks his collection and sees that one of the revolvers stored in a leather holster is missing.

Sir Henry shares his experiences with his wife, but Lucy is more concerned about the upcoming wedding of Henrietta and Edward.

Henrietta comes to Villa Poirot. She admits that he and John loved each other, but is it worth it to tell the police? Henrietta tells the famous detective about John’s relationship with Veronica Cray and Gerda. That day, Henrietta left the forest and saw Gerda with a revolver in her hand. She was afraid that the awkward Gerda would shoot at someone and wanted to take her weapon, but Gerda dropped him into the water. When asked by Poirot if Henrietta had shot, the girl grins: if she shot, she would have wiped her fingerprints. And he named her name before death because he loved her.

On reflection, Poirot decides: what he saw at the pond is a scene.

Inspector meets with Veronica Creil. The actress believes that John was shot dead by his extremely jealous wife. According to the maid of the actress, John and Veronica quarreled, and she said she hated him.

Poirot and the inspector are trying to understand what happened. They decide that the killer wanted to blame Gerda and suspect Veronica and Henrietta. Suddenly, one of the maids reports that on Sunday afternoon she saw a butler with a revolver. The butler found a weapon in the hall - a toy Mauser from which you cannot kill. Lucy declares that the butler is a servant of the old school, he cannot betray the masters. The weapon was found in a basket of eggs. Out of distraction, Lucy put him in a basket and went with her to the farm. Having laid eggs there, she forgot about the weapon and asked the butler to take the basket to the kitchen. The butler found the Mauser and put it in its place.

Left alone with her husband, Lucy discusses with him the situation in the family. She is worried about the estate that went to Edward. If he does not marry, then the family will disappear. Now that John is dead, he can marry Henrietta.

Veronica Creil comes to Poirot. The actress says that he and John recalled the past. John lost his head and began to insist that she abandon the family and marry him, but the actress rejected him. The famous detective does not believe her. It was John who pushed her, and the actress is suffering from humiliation.

Henrietta sculpts a horse in his workshop. The horse turns out to be a bit abstract, but this does not bother the sculptor.

After a weekend at Hollow, Edward looks at Henrietta and Midge with different eyes. Now Midge is not a familiar “baby” for him, and Henrietta is no longer the same. Edward comes to Midge to work. Seeing how rude the customer is talking to her, Edward invites the girl to marry him and go to his estate with him. Lucy enthusiastically accepts this news and promises to help Midge with the dowry.

Hercule Poirot comes to the pond, near which the murder took place. There comes Henrietta. Talking with the detective, she draws the same tree as was painted in the pavilion.Henrietta is trying to make excuses, but Poirot realizes that she was in the pavilion in the morning and from there watched what was happening at the pond.

Poirot with the inspector discuss the situation. Near the pond were Lucy and Henrietta with baskets and Sir Henry in a hunting suit with large pockets. Everyone could hide weapons, because the police searched the whole house and did not find it. Everyone has an alibi, everyone has been watched. Poirot is interested in horse sculpture in the workshop of Henrietta.

At the suggestion of Poirot, the inspector inspects the area near the house and finds weapons there, but it has nothing to do with the murder. The investigation is at an impasse.

Midge and Edward arrive at Hollow. The girl breaks the engagement, she does not want to marry a man who does not love her. At night, Midge hears some footsteps, goes downstairs and sees Edward, who has decided to poison himself with carbon monoxide. Midge was the only thing left for him. As a writer, he was worthless, and Henrietta rejected him. Midge stays with him.

Lucy comes to Henrietta. Both women worry that investigators may find a gun holster.

Henrietta comes to Gerda and asks to give her a holster. Gerda cut it into pieces and hid them in a needlework bag. She followed John and saw him with Veronica. Gerda still believed him, but now decided to kill him. Gerda knew that weapons could be identified. Taking two revolvers, one she decided to kill and hide him, and the second to hold in her hands.

Gerda offers Henrietta tea, but Henrietta demands that Gerda bring a holster. Hercule Poirot suddenly appears. He advises Henrietta not to drink tea. Gerda, who came, drinks tea and dies. The famous detective says the poisoned tea was for her. Like a wolf caught in a trap, Gerda tried to bite even the one who wanted to free her.

From the very beginning, Poirot suspected that a performance had been played in front of him. Hearing that before death, John called her name, Henrietta realized: he asks to save Gerda. She deliberately dropped her weapon into the pond so that her fingerprints disappeared. But when she learned that John was killed from another revolver, she guessed where Gerda could hide him. Finding a weapon, Henrietta hid it in a horse sculpture. Lucy realized that Henrietta was trying to save Gerda, and played along with her.

Poirot will hide the truth, let them think that Gerda committed suicide in a mental breakdown.