十九岁阿磊（陈柏霖 饰）跟很多时代年轻人一样喜欢追星，他与几个死党都喜欢五月天这个乐队，更一起维护属于五月天的网页，他们竟然充当乐队的成员给其他歌迷回信。阿磊在网络上以虚拟的身份结识了同样喜欢五月天的瑄瑄（刘亦菲 饰），瑄瑄是哈尔滨京剧团的学生，她趁着随团到台北表演的机会偷偷到了三义。瑄瑄要求与阿磊见面，更要求阿磊能带她到三义去，更不可思议的是当他们来到了三义，瑄瑄要求阿磊闯入一位老妇人的住宅里。两人双双被带到警察局。这时候阿磊才知道她是来自哈尔滨的，却不明白她要到三义去的原因，对于瑄瑄的行为也深感困惑。然而，短短的数天相处中两人的情感更加深厚了。瑄瑄还是离开了台北，阿磊却与她失去了联系。日夜想念瑄瑄的同时，阿磊也决定到三义，去发掘瑄瑄的秘密…

台灣版《電子情書》，一段由網路謊言相識的浪漫愛情，大明星劉亦菲、陳柏霖及當紅人氣偶像團體五月天銀幕處女作，是一部令人無法抗拒的清新小品。

Ah Lei is the younger brother of Stone, a guitarist of Mayday. He is also the administrator of Mayday's fansite, in charge of replying to fan letters and emails. One day, he befriended a girl named Zhao Xuan through a chatroom. He told her that he's actually Ashin, the lead vocal of Mayday. She started writing letters to him, believing that he was Ashin. Finally, Xuan's peking opera group from school gets to leave Harbin and travel to Taiwan to perform. The two promised to meet in a library, but Ah Lei didn't have the courage to meet up with her. He decides to follow her around, but did not expect that she followed him back, and that she saw through his lies all along.