影片讲述的是一名少女由于身患绝症，无法被太阳所照射，只能生存在黑夜之中，晚间出来活动，这个少女十分热爱生活，也喜爱歌唱，这个美丽少女遇到心仪男孩的故事

女主凯蒂在幼时患上了极为罕见的着色性干皮症，对于常人来讲，生活无处不在的紫外线在照射凯蒂身上时会造成致命创伤。在无奈之下，凯蒂只能选择白天太阳未落山时呆在家中，常年以吉他弹奏乐曲为乐趣，夜晚到来之时，凯蒂开始活动，带上心爱吉他，到火车站自弹自唱。

一人名叫查理男子被凯蒂歌声吸引并驻足观看，查理被凯蒂开朗活泼的性格所吸引，深深爱上了凯蒂。凯第一没有想到查理是自己曾暗恋的男子，为了保护这段感情，凯蒂决定隐瞒自己的病情，但总有一天，病情会暴露出来，这段感情将何去何从？

The film is about a girl who is terminally ill and cannot be exposed to the sun, so she can only live in the dark and come out at night. She loves life very much and also loves to sing. The story of this beautiful girl who meets the boy she likes

The heroine Katie suffered from Xeroderma pigmentosa is extremely rare. For ordinary people, the ubiquitous ultraviolet rays in life will cause fatal trauma when they irradiate Katie. In desperation, Katie can only choose to stay at home during the day before the sun sets, and enjoys playing guitar music all year round. When night comes, Katie starts activities, brings her beloved guitar, and goes to the train station to play and sing by herself .

A man named Charlie was attracted by Katie's singing and stopped to watch. Charlie was attracted by Katie's cheerful and lively character, deeply In love with Katie. Katie never thought that Charlie was the man she had a crush on. In order to protect this relationship, Katie decided to hide her illness, but one day, the illness will be exposed, and where will this relationship go?