Pin

Dr. Frank Linden uses a life-size medical dummy named 'Pin' in his office to teach his children about bodily functions. Through ventriloquism, Pin speaks and explains how the body works in a way that feels approachable to Leon and Ursula. Pin becomes the one bright, playful sign of warmth in an otherwise emotionally distant household.

Unknown to Linden, Leon is mentally ill and comes to believe Pin is alive. His mother discourages outdoor play and forbids friends, leaving Leon with Pin as his only confidant. The bond with Pin seeds an escalating delusion that will shape his future.

Leon secretly witnesses a nurse using Pin as a masturbatory sex doll. The shocking scene deepens his fear of women and seeds a crippling mistrust of female sexuality. This traumatic event becomes a touchstone that informs his later violence and paranoia.

During their school-age years, Leon and Ursula discuss the sex education they've received. Ursula admits she is looking forward to becoming older and experiencing desire. The conversation highlights a growing, complicated fascination with bodies and boundaries.

At a high school dance, Leon discovers graffiti claiming Ursula sleeps around. He finds her in a car with a boy and assaults him, forcing her to promise never to do this again. He later learns Ursula is pregnant, and, through Pin, insists they tell their father who then performs an abortion on Ursula.

When Leon turns eighteen, Dr. Linden, planning to use Pin as a visual aid for a speech, realizes the extent of his son's psychosis. They speed toward the medical school hall, but a car crash kills both Linden and his wife. Ursula and Leon survive, immediately shattering their family life.

Grief-stricken, Ursula and Leon become orphans. Aunt Dorothy, their mother's sister, moves in to help, while Ursula begins a job at the local library. Leon resents Aunt Dorothy's influence and worries about Ursula's independence.

Leon's fixation with Pin escalates and he uses Pin to frighten Aunt Dorothy, causing a fatal heart attack. Ursula is shaken by the loss and begins researching mental illness, realizing Leon's paranoia may be driving the events around them.

Ursula meets handsome Stan Fraker while continuing her library work and falls in love. She remains unaware of Leon's growing paranoia and his fixation on Pin. Leon's suspicion that Stan is after Ursula's inheritance begins to color his actions.

Leon invites Stan to the house under the pretense of planning a surprise party. He drugs Stan's drink and, when Stan resists, bludgeons him with a sculpture. Following Pin's supposed instructions, he places Stan's body in a bag and hides it in the woodpile, making it look like a disappearance.

Ursula suspects something is wrong when she hears Stan's beeping watch and finds a damp spot on the carpet. Leon blames Pin, but Pin reminds him that they cannot lie to themselves. In a panic, Ursula returns home with an axe, ready to strike, and the scene ends with a white-out as Leon screams.

Police later discover that Stan's body is still alive, revealing a shocking survival. Ursula and Stan return to the house to visit Pin and discuss her future with him. Pin asks if Ursula has heard from Leon; she says no, and Pin laments the missing bond with his 'brother'.

As the story ends, Ursula speaks to Leon, who has taken Pin's persona and lives in the dummy's skin. The ventriloquism act becomes literal in a terrifying split personality, suggesting Pin's persona has survived as Leon's new self. The film closes on the chilling implication that the brother's danger is far from over.