Dementia

John Haloran and his wife Louise find themselves in a tense argument while rowing on a dark lake. The dispute centers around John's wealthy mother's will, which bequeaths everything to charity in the name of a mysterious figure named Kathleen, leaving Louise frustrated and worried about their financial future.

During their argument, the physical exertion causes John to suffer a sudden heart attack. In a shocking moment, John informs Louise that if he dies before his mother, she will inherit nothing, and shortly after making this revelation, he passes away.

In a desperate attempt to secure her future, Louise decides to dispose of John's body. She dumps his corpse over the side of the boat, watching it sink to the depths of the lake before formulating a plan to convince his family that he is still alive.

Louise invites herself to the Haloran family castle in Ireland, crafting a letter to her mother-in-law, Lady Haloran, under the pretense that John is away on business. This marks the beginning of her deceptive plan to ingratiate herself with the family and secure a place in the will.

Upon arrival at the castle, Louise witnesses a bizarre annual ceremony held by John's brothers, Billy and Richard, in honor of their deceased sister Kathleen. The event is deeply emotional for the family and particularly for Lady Haloran, who has mourned Kathleen's death for years.

During the ceremony, Lady Haloran faints, a recurring event that prompts Louise to help her inside. As they enter the castle, Lady Haloran reveals that she believes her fainting was caused by the death of a flower she threw on Kathleen's grave, highlighting her superstitions and emotional state.

Recognizing Lady Haloran's vulnerability, Louise devises a plan to convince her that Kathleen is trying to communicate from the grave. She secretly takes Kathleen's old toys and places them at the bottom of the estate's pond, hoping they will float to the surface and create a ghostly appearance.

While executing her plan, Louise unexpectedly encounters what appears to be Kathleen's perfectly preserved corpse at the bottom of the pond. Horrified by this shocking revelation, she resurfaced only to be violently attacked by an unknown assailant wielding an axe.

The family doctor, Justin Caleb, arrives to unravel the mystery surrounding the recent violent acts. He begins to question the family members, attempting to piece together the events leading up to the tragic occurrences, but tension runs high amidst the fear and suspicion.

As the investigation unfolds, a shocking murder occurs on the estate where a man named Simon is decapitated for poaching. This gruesome act adds more layers of danger to the unfolding drama, as the killer remains at large, preying on innocent victims.

That night, a shadowy figure attempts to attack Lady Haloran again. In a state of panic, she manages to evade her attacker but collapses from the stress in the castle courtyard, heightening the sense of dread surrounding the family.

Dr. Caleb employs hypnosis on Billy to extract information hidden deep within his subconscious. He discovers a nursery rhyme that serves as a crucial clue leading him to uncover Louise's frozen corpse, hidden in a meat locker alongside a wax figure of Kathleen.

To draw out the killer, Dr. Caleb places the wax figure of Kathleen in a public square. This daring move is designed to lure the murderer into the open, exposing their identity and intentions, as the atmosphere grows even more tense.

Under the strain of overwhelming guilt for his sister's death, Billy becomes increasingly unstable and attempts to kill Richard's fiancée, Kane. His break from reality culminates in a frantic attack where his motives become chillingly clear.

In a dramatic climax, Dr. Caleb intervenes just in time to save Kane from Billy's lethal assault. He bravely shoots Billy, ending the cycle of violence and bringing a moment of relief to the terror-stricken family, albeit with a heavy toll of loss.