A group of close friends who attend a private school all have a debilitating crush on the sunny star pupil, Shen Chia-yi. The only member of the group who claims not to is Ko Ching-teng, but he ends up loving her as well.

Peking, 1948. A winter night. A man returns home to find a letter awaiting him written by a woman before her death. in the letter she tells him the story of her love for him -a life-long passion that has not diminished over time, but one that he has never known. her story spans 18 years from the moment she -then a 13 year-old girl- sets her eyes on her new neighbor. she tells their brief but passionate love in her youthi the hardship she goes through raising their child alone, and their final encounter after the war, during which the man fails tor ecognize her and one which leaves her in despair. Now having lost her son, she no longer has the courage to live on. Only in a letter is she capable of telling him everything, for the first and the last time. shaken by the letter, the man searches his memory for the nameless woman.

《槲寄生》延续了蔡智恒小说一贯的浪漫气氛，描述“我”实在不是故意，但仍旧不小心同时爱上两个女孩的“三角恋”故事：在台北担任研究助理的“我”，打开抽屉，随手拿出一根烟抽，要把烟拧息时，发现烟上有字……
每抽一根烟，便忆起一段往事。最让他心动的是她，那个在烟上写字的女孩；可另一个她也叫他痛苦，那是让他重拾信心的女孩。当你令两个女孩心痛，你就不得不做一个选择；当两个女孩令你忆起左肩右肩痛，你就知道自己中毒太深，要细细分辨，什么是真爱，什么是一生所爱……
爱抽MILD SEVEN的蔡智恒，用十根烟串起一个浓淡相宜的爱情故事，就像《第一次的亲密接触》一样，其中或多或少难免糅进自己切身的情感经历。