艾米想要发一封电子邮件取消“来客”杂志的订阅，却因一字之差，误将邮件发送给了里奥。在艾米三番两次寄错邮件后，里奥的善意提醒，却未能阻止艾米继续来信。两人在虚拟世界开始了交流。里奥刚刚结束一段失败的感情，而艾米虽号称自己婚姻生活“幸福美满”，却意识到这段婚姻逐渐消磨掉了爱情最初的美好。两个素未谋面的人，通过一封封邮件交换秘密，倾诉生活点滴。里奥与艾米从最初的互相看不顺眼，到产生兴趣、建立信任，他们相互慰藉，也开始对彼此产生了不一样的感情……

For years, Martin has been working on his great play about cloud castles, flying pirates and a feisty princess. His secret role model for the leading character is his good friend Isabel, a cheeky young woman who is waging war on genetically modified seeds around the world. And she is leaving tomorrow to go to the middle of Africa for the next three years. Low and behold, Martin confesses his love to her at the departure desk. A confession which would have meant the world to Isabel some time ago, but now comes too late to change things. But then the flight is delayed for several hours. Isabel takes off into the city to talk to Martin, but he has disappeared...