Watchmen is set in 1985, in an alternative history United States where costumed adventurers are real and the country is edging closer to a nuclear war with the Soviet Union (the Doomsday Clock is at five minutes to midnight). It tells the story of a group of past and present superheroes and the events surrounding the mysterious murder of one of their own. Watchmen depicts superheroes as real people who must confront ethical and personal issues, who struggle with neuroses and failings, and who - with one notable exception - lack anything recognizable as super powers. Watchmen's deconstruction of the conventional superhero archetype, combined with its innovative adaptation of cinematic techniques and heavy use of symbolism, multi-layered dialog, and metafiction, has influenced both comics and film.
Watchmen is set in an alternate reality that closely mirrors the contemporary world of the 1980's. The main difference is the existence of superheroes. Their presence in this history has altered the outcomes of real-world events such as the Vietnam War and presidency of Richard Nixon. Although the cast of Watchmen are commonly called "superheroes," the only character in the principal cast who possesses superhuman powers is Dr. Manhattan. In the comic, they refer to themselves as "costumed adventurers."
The cast of Watchmen was initially based upon old MLJ Comics and then Charlton Comics characters. The Comedian (Edward Blake) is based on Peacemaker. Doctor Manhattan (Jon Osterman) is derived from Captain Atom, while the first and second Nite Owls (Hollis Mason and Dan Dreiberg) are based upon Blue Beetle. Thunderbolt serves as the inspiration for Ozymandias (Adrian Veidt), while the Question and Mr. A do the same for Rorschach (Walter Kovacs). Finally, the first and second Silk Spectres (Sally Jupiter and Laurie Juspeczyk) are roughly analogous to Nightshade, but only in that they are female. Moore has stated that the Silk Spectres are more directly inspired by elements of Black Canary and Phantom Lady.
The graphic novel Watchmen is composed of twelve chapters. These chapters were originally separate issues of the comic book series, which were released sequentially starting in 1986. Each chapter begins with a close-up of the first panel, originally the cover to each issue. Each chapter has an epigraph from classical or pop literature, which appears in abbreviated form early on, and acts as the chapter's heading or title. The quote is given in its entirety at the end of the chapter, summarizing the events that have just occurred.
Watchmen also contains many fictional primary documents, which are appended to the end of every chapter (except the final one), and are represented as being a part of the Watchmen universe's media. Biographies of retired costumed adventurers, such as the retrospective Under the Hood by the retired first Nite Owl, are used to help the reader understand the chronology of events, and also the changes in public opinion and representation of costumed adventurers through the decades. These documents are also used to reveal personal details of the costumed adventurers' private lives, such as Rorschach's arrest record and psychiatric report. Other documents used in this way include military reports and newspaper and magazine articles.
When reading Watchmen, the reader is mostly presented with only an objective point of view, able to see all the characters' actions, facial expressions, and body language; but, in a move unusual for comic books of its time, Moore did not use any thought balloons to clarify his characters' thoughts, although several sections consist of long episodes that replay the characters' memories or include entries from diaries. The documents that are appended to the end of each chapter except the last, as well as media such as Rorschach's diary, help to elucidate characters' thoughts and feelings throughout the novel, without mentioning them explicitly. This is in keeping with Watchmen's largely cinematic presentation.
First person perspective is also used, albeit less frequently. Flashbacks are employed to help facilitate the reader's understanding of events occurring in the present, but also as a means of chronicling the differences in history between the Watchmen universe and our own. Thus, Dr. Manhattan's flashback to the Vietnam War highlights how both his and the Comedian's existence altered their world's history in comparison to our own.