NJ Jian, his wife Min-Min and their two children, the shy adolescent Ting-Ting and her brother, the precocious philosopher Yang-Yang, are a typical middle-class family. Seemingly comfortable in their Taipei apartment, they are about to discover how unstable their lives really are. Things start to go wrong, on the day that Min-Min's brother gets married, with the unexpected arrival of his ex-fiancée. Yi Yi is strung together by troubling duplications, sudden reversals of fortune and astonishingly exquisite parallels.