Although Aristotle, in his Poetics, gives priority to "the structure of incidents" over character, he notes that character and plot are interdependent, since action arises from character, and character is expressed through action
A plot may be said to have "unity of action" if all its parts contribute to the whole with nothing superfluous. Renaissance critics disapproved of the mingling of tragedy and comedy because it seemed to violate this sacred unity, but they only showed a narrower sense of unity than the writers of the time.
The main character in a literary work is the protagonist, and her or his adversary (if there is one) is the antagonist (as Iago is to Othello). Most plots centre upon a conflict, or multiple conflicts: the protagonists are set against other people or society; against fate, circumstance or the environment; or against their own desires or values; or any combination of these. If characters scheme against someone else, exploiting their ignorance or credulity, they are said to intrigue.
One common model for plot structure consists of the rising action (or complication), in which the main conflict is developed; the crisis or turning point, when the tragic hero is at the height of fortune or the comic hero at a nadir; and the catastrophe, or denouement ("unknotting"), when the action is resolved unsuccessfully or successfully for the main character.
The denouement often involves a peripety, or reversal of intention, whereby the protagonist's intended outcome is reversed for better or worse; and this reversal often depends upon a recognition, or discovery, which radically changes the protagonist's understanding of her or his circumstances. In double plots, a secondary story (the subplot) parallels the main one, either as an analogy (the story of Gloucester in King Lear) or as a contrast with the main story (the comic subplot of Henry IV, Part 1).
A plot can create suspense by arousing sympathy for a character whose fortunes are uncertain, leaving the audience or reader anxious for the sake of the protagonist. On the other hand, the plot can also generate suspense when the reader is allowed to know the final outcome and is then shown the protagonist's step by step approach to an end he or she does not expect (see dramatic irony). For some of the plot patterns used to achieve particular overall effects of tragedy, see the entries on comedy, romance, or satire.