The story begins on a fine summers morning, when Sang-woo (Yu Seung-ho) and his mother board a bus to the country. It is soon clear that the unsophisticated rural passengers annoy the seven-year-old urban boy. His mother is taking him to live with his 78-year-old mute, but not deaf, grandmother (Kim Eul-boon) while she looks for a new job after a business venture failed in Seoul. Eventually they reach their destination, a dusty bus stop in the Korean countryside near an unsophisticated village.By now Sang-woo, who has arrived with junk food and toys, has no intention of respecting his mute grandmother especially as her house has neither electricity nor running water. His mother apologises for leaving the boy, telling her own mother it will not be for too long before leaving on the next bus. Alone Sang-woo ignores his grandmother, not even wanting to look at her and even calling her a byungshin, or "retard". Next morning, his grandmother starts another day. She goes down the hill to get clean water and washes her clothes at the river. She also tends the melons that she will sell at the market.One of the Grandmother's neighbours is a hard-working country boy who attempts to become friends with Sang-woo, who declines until the end when he apologizes for making fun of him. The other is a young girl who Sang-Woo falls in love with, but she is more interested in the country boy.The grandmother, who also cares for her old friends very much, lives a simple and humble life. Eventually, from constant play, Sang-woo's Game Boy runs-out of batteries so he asks his grandmother for money for new ones. But she is poor and has none. Selfishly he teases her, and in an intolerant manner throws away her shoes, breaks one of her vases and draws graffiti on her house walls.When this fails to get money from his grandmother, Sang-woo steals her ornamental hairpin to trade for batteries. He then goes off to find the shops. When he finally finds the right place he attempts to trade the silver hairpin but instead of getting batteries the shop keeper, who happens to be his grandmother's friend, hits him on the head and sends him home.One day Sang-woo demands Kentucky Fried Chicken. But as the grandmother only understand "chicken", she takes some of her melons and trudges off to the market to buy a chicken. Bringing back a live one in the rain, she prepares a home-made boiled chicken instead of fried chicken. When Sang-woo wakes up he sees the boiled chicken he gets angry, throwing the food away. Later in the night he finishes the food because he is hungry. The next morning, his grandmother becomes ill and Sang-woo serves her the remaining chicken while caring for her.Despite the hardships faced by the old grandmother who has osteoporosis, the only thing she needs Sang-woo for is to run thread through her needles. She stitches the shoes and shares her earnings with a friend who ends their meeting with the words "Come by again before one of us dies."Sang-woo remains angry and confused by the unfamiliar environment and repeatedly rejects her attempts to please him. But her unconditional love slowly touches his heart. One day, Sang-woo gets up early and goes with his grandmother to the market where he sees how hard his grandmother persuades passers-by to buy her vegetables. After a long day at the market she takes Sang-woo to a shop and buys him noodles and new shoes. When they are about to board the bus home, Sang-woo asks his grandma to buy him a Choco Pie.The grandmother goes to a shop that is run by an elderly friend. The shopkeeper, who now has a bad knee, gives her five or six pies but refuses to take any money, so the grandmother gives the shopkeeper a melon. But when the grandmother returns to the bus with the sweets, Sang-Woo says he wants to ride alone as the girl he likes is also on board. The grandmother tries to get Sang-Woo to take the rest of the produce with him but he refuses. The bus then leaves. Sang-Woo then has to wait for his grandmother to return wondering why it is taking her so long. He then realises that his grandmother has walked back from town carrying all her produce.Eventually Sang-woo begins to love his grandmother, but because she is unable to read or write he makes some simple greeting cards, so she has some letters from him. Finally Sang-woo's mother returns and he goes back to Seoul. His depth of feeling for his grandmother are revealed when the bus leaves and he leaps to the back window to wave his tearful farewells. The film closes with the grandmother continuing to live alone in the thatched-roof house but with the letters of love from her grandson.
Output: Question: How old is Sang-woo's grandmother?, Answer: 78 years old.