After 10 years of marriage, Do-il and Mi-sook live a seemingly happy and secure life together. Unable to conceive, they decide to adopt Jin-Sung, a young boy. Quiet and introverted, Jin-Sung spends most of his time playing underneath the Acacia tree in their backyard, away from the family. When Mi-sook becomes miraculously pregnant, he becomes even more detached. As the once-dead Acacia tree in the backyard begins to bloom, terrible "accidents" start to tear the household apart.