After 18 months Sam returns to his place of birth. He wants to ask his girlfriend Meg who he had let down when he left, to go with him to the big city. However Meg was deeply sad because of Sam's leaving, that she had started a relation with his best friend Johnny. At the night of Sam's unexpected return, Johhny asks Meg to marry him. Meg is forced to make a choice! That Saturd...
作家梅尔文（杰克·尼科尔森 饰）是一个脾气古怪的强迫症老头，没有家庭也没有朋友，整天关在屋里写他的第二十六部小说，生活如时钟般精准，受不了一点的打扰。
梅尔文的邻居西蒙（格雷戈·金尼尔 饰）是年轻的同性恋画家，养了一条可爱的小狗，生性活泼，脾气温和，经常受到梅尔文的侮辱 。
梅尔文每天只出门一次，到同一家餐厅吃饭，餐厅女招待卡罗尔康奈莉（海伦·亨特 饰）是唯一愿意而且能够为他服务的人。离了婚的卡罗尔与儿子斯潘塞住在一起，斯潘塞患有严重的哮喘病，这使得许多对卡罗尔有意思的男子知难而退。
一天，西蒙的住所遭到抢劫，西蒙身受重伤，住院前，将小狗托付给梅尔文照料，梅尔文渐渐喜欢上了这个小家伙，心理也发生了变化，开始关注周边的世界，主动帮助别人，认真审视自己对卡罗尔的好感……
