The Housemaid (1960, S. Korea) (aka Hanyeo)

In writer/director Ki-young Kim's psychological horror thriller and lurid domestic melodrama set in post-war Korea, it covered the themes of marital infidelity and predatory sexual obsession of the title character - the 'housemaid', mixed with a critique of traditional and materialistic bourgeois values:

• in a pre-credits sequence, a husband was speaking to his wife while reading a newspaper account about a businessman who committed adultery with a housemaid and brought terrible consequences upon his family (Husband: "A man in Gimcheon committed adultery with his maid" Wife: "Men are hopeless, taking interest in a maid" Husband: "I disagree. Look at us. We're almost totally dependent on our maid. She cooks and washes for us, and is the first person to greet me when I come home from work. She is fully at our service" Wife: "Such thoughts should not be said or practiced in our sacred household") - the scene and its dialogue was a clue to the film's framing device (with a surprise ending) and a premonition of what would happen
• the opening title credits (with dripping blood in B/W) were superimposed above the unsettling and long game of cat's cradle (a metaphoric symbol of web entrapment) played by the couple's two children
• the main characters, a family of four, who lived in a claustrophobic, two story western-style, South Korean house included: handsome pianist, part-time composer and music teacher Mr. Kim Jin Kyu (Dong Sik), his pregnant seamstress wife Mrs. Kim (Ju Jeung Ryu), and their two children: crippled older daughter Ae-soon (Yoo-ri Lee) with crutches, and younger mean, selfish and bratty son Chang-soon (Sung-kee Ahn)
• the family hired unstable, pig-tailed, chain-smoking, "not too bright" textile factory worker Myung-sook (Lee Un-shim) as the family's housemaid, who began behaving unpredictably, erratically, capriciously and strangely -- almost immediately, she chased and caught a rodent with her bare hands in the kitchen and had an unusual smile on her face as she held up its corpse by the tail
• she developed an obsession with rat poison kept in the kitchen cupboard, voyeuristically spied on Kim giving piano lessons through a sliding glass door, taunted the children, and banged on the piano in the middle of the night
• pivotal events: the seductive Myung-sook forced herself on Mr. Kim in her bedroom by letting her top drop at her balcony door; not able to resist her half-nakedness, he grabbed her breast from behind, and she stood barefooted on his shoes; she locked her hands around his back before they had sex (off-screen, and symbolically, a tree was struck outdoors by lightning!) - and afterwards she became pregnant
• the housemaid used blackmailing techniques to try to insinuate herself between Mr. Kim and his wife; the scheming Mrs. Kim learned of her husband's infidelity when he confessed to her, and she assured him: "I'll beg the girl on my knees...We can't let our precious lives be destroyed now"; moments later, she suggested that the housemaid throw herself down the tall stairway to induce a miscarriage and abort the baby (the incident was heard off-screen); also at the same time, the housemaid jealously threatened to kill Mrs. Kim's newborn baby son

The Deadly Stairway: The Housemaid's Miscarriage

The Younger Son's Death at Foot of Stairs

• the same stairway caused the death of the younger son (he had been tricked by the vengeful housemaid into believing he had drunk from a glass of rat-poisoned water), and as he ran to tell his parents, he tripped and fell down the stairway and died at the foot of the stairs; remarkably, the jealous housemaid coerced them to agree that the husband could sleep in her upstairs bed: ("I want the father of my child"), so that she could bear him another son!
• the wife in desperation ("I only wanted to save my family from this living hell") attempted to poison the housemaid, but the intended target had substituted sugar for the rat poison and became wise to the murder attempt
• in a horrifying scene, the housemaid terrified the daughter by force-feeding her - stuffing her mouth with possibly-tainted rice
• in the film's unforgettable climax (a memorable death scene), the crazed housemaid urged Mr. Kim to commit a double-suicide with her by ingesting rat poison dissolved in glasses of water: ("That'll make the living happy - Die with me! Make me the happiest woman!"); as they were dying from the poison, she gave a deranged speech: ("Don't worry. I'll be with you for eternity. I'll ask God to perform our wedding ceremony. The flowers will never wither, while the paths will glitter with jewels. And nobody will ever take you away from me" - lightning struck )
• Mr. Kim decided to climb down the stairs to die by his wife's side: ("You can take my body, but not my soul"), but the housemaid resisted his last request: ("If I lose you now, I'll never find you again in heaven"); she grabbed onto his left leg and ankle and was dragged down each step - with her head pounding or thumping into each stair-step; she either died from the poisoning or from a damaging head concussion; when he crawled into his wife's sewing room and collapsed dead at her feet - she spoke regretfully: "Oh, if only I hadn't wanted the new house"

Memorable Death Scene: The Housemaid's Death on the Stairs

• the stunning and jarring plot twist ending (none of the deaths from the rat poison or the stairs had occurred) -- the camera pulled back to find both husband and wife alive; the scene returned to the opening pre-credits sequence; the entire story was a cautionary "what if" tale between the husband and wife:
  
  Wife: "I don't see how a man of good character could lose his head over a maid."
  Husband: "That's man's weakness. A high mountain challenges him to climb it. A deep lake prompts him to throw a rock into it. A beautiful girl stirs his most primitive desires."
  Wife: "Indeed! Men are beasts!"
  

Plot-Twist Ending

• suddenly, the sliding door opened, and the housemaid delivered a tray of tea to the family! and then the husband broke the fourth wall and addressed the camera and audience, before ending with a laugh: "Ladies and gentlemen, as men get older, they spend more time thinking about young women. That's how they get drawn into women, which could lead to their destruction. This is true for all men!"