计程车司机柏（太保饰演），以及退休单亲爸爸海（袁富华饰演），即使大半生受尽传统社会的规范与约束，两人仍对多年来努力建立的家庭为荣。不过，两人没料到能在人生的最后这段路上，与彼此邂逅…。
柏与清（区嘉雯饰演）结婚45年，育有一子一女，可谓上一代传统香港人眼中「幸福家庭」的典范。海的太太早年离他而去，与儿子永（卢镇业饰演）相依为命。虽然海与儿子一家同居，却无法感受到家的温暖。而柏与海迟来的相遇，也翻搅起两人尘封心底的爱慾。面对「爱情诱惑」与「社会道德价值」的拉扯，以及内心「原始慾望」跟社会传统「幸福家庭」的抉择，两人究竟要回归最原始的自己？还是重返风平浪静的生活，继续守护社会价值观所认可的「美好家庭」呢？
Ga-yeon comes to Min-jae's house where he lives alone, and decides to live there. Min-jae is curious about Ga-yeon who he haven't seen in a long time. One day, Geon-soo goes to Min-jae's house to pick up some stuff and meets Ga-yeon. Ga-yeon seduces him. Min-jae finds out about it when he phoned Geon-soo. Da-hae meets Min-jae to become sex partners and frequently contacts each other.
Min-jae gets angry at the sight of Geon-soo wearing only underwear at his house. Gayeon comes out to meet her friend Da-hae after a long time. Ga-yeon and Da-hae who were drinking, join after seeing Min-jae and Geon-soo. That night, Min-jae gets drunk and had sex with Ga-yeon and finds out that Da-hae is not in a relationship with Min-jae. The next day, Ga-yeon knows the relationship between Da-hae and Gun-soo, and she brings the four people together...
