影片的男主角基顿（巴斯特·基顿 Buster Keaton 饰）是一名乡村影院电影放映师，他喜欢阅读侦探类的书籍，经常幻想自己就是一名像福尔摩一样的大侦探。一天，他把价值一元的巧克力糖谎称四元送给女友凯莎琳（Kathryn McGuire 饰），不料被情敌趁机陷害，说基 顿偷了别人的手表拿去当才有钱买巧克力。凯莎琳相信了谗言，遂将基顿赶出门外，并取消了二人之间的婚约。基顿查访之后，发现情敌才是偷表典当的家伙，但却苦无证据洗清冤情。某日，基顿在放映电影时，发现银幕上的故事竟和他的遭遇同出一辙，而且人物也雷同，唯一不同的是电影中的故事发生在一个上流家庭而已。基顿边放映电影边沉溺在电影之中，于是走出放映室，从观众席走入银幕之中逮捕情敌罪犯。可是进入银幕后的基顿却四处碰壁，一筹莫展．随着场景的变化，银幕上的映象不断从幻想变成事实……

某富豪财大气粗，高薪聘请专家将他的别墅改造成全自动化现代房屋。拥有植物学博士专业头衔的青年（巴斯特·基顿 Buster Keaton 饰）参加应聘，却在阴差阳错之中和邻座的两人将学位证书搞混，变成了电气学专业的博士。青年有心反悔，但看在富翁女儿貌美如花、亲近可人的份上，也就应承了下来。
不久后，富翁一家驱车度假，留下青年一人改造房屋。他临时抱佛脚，凭借一本电气学基础知识的课本大刀阔斧干了起来。时间转瞬即逝，数日后富翁返回，等待他们的是一座令人难以想象且叹为观止的全自动化现代房屋……

When Keaton is rejected by his girl friend, he sets out in a small boat seeking forgetfulness. His troubles increase, however, when he takes refuge on a whaling ship. He quickly incurs the wrath of the despotic ship's captain. Making his escape, Buster next encounters a large flotation device which he does not recognize as a target for nautical maneuvers. It is blown to smithereens and Buster wakes up from a dream. We realize the whole story has been a dream. And Buster, to his consternation, discovers his own small boat has never left the dock.
Color: Black and White
Sound Mix: Silent

This very Kafka-esque film is Keaton's response to the Fatty Arbuckle scandal.[citation needed] Even though the central character's intentions are good, he cannot win, no matter how inventively he tries. He gets into various scraps with police officers throughout the film. Eventually, he unwittingly throws a bomb into a police parade and ends up being chased by a horde of cops.
At the end of the film, Keaton's character locks up the cops in the police station. However, the girl he is trying to woo disapproves of his behavior and gives him the cold shoulder. Therefore, he unlocks the police station and is immediately pulled in by the cops. The film ends with the title "The End" written on a tombstone with Keaton's pork pie hat propped on it.
One of Keaton's most iconic and brilliantly-constructed short films, Cops was deemed "culturally, historically, or aesthetically significant" by the United States Library of Congress and selected for preservation in their National Film Registry in 1997.