Mills and Somerset are detectives trying to catch a serial killer known as John Doe who is murdering people based on the seven deadly sins. The trailer uses dark cinematography and editing to set a gloomy tone, showing gruesome crime scenes without revealing full details to build mystery. It establishes the characters of Mills as a hot-headed rookie and Somerset as a wise but tired veteran, and hints their differing approaches may cause conflict in solving the complex case. The trailer intrigues viewers by implying the killer is always one step ahead and the graphic nature of the unsolved murders will take a psychological toll on the detectives.