In a literary work, film, story or other narrative, the plot is the sequence of events where each affects the next one through the principle of cause-and-effect. The causal events of a plot can be thought of as a series of events linked by the connector "and so". Plots can vary from the simple—such as in a traditional ballad—to forming complex interwoven structures, with each part sometimes referred to as a subplot or imbroglio. In common usage (for example, a "movie plot"), however, it can mean a narrative summary or story synopsis, rather than a specific cause-and-effect sequence.