MacGuffin

In fiction, a MacGuffin is a plot device in the form of some goal, desired object, or other motivator that the protagonist (and sometimes the antagonist) is willing to do and sacrifice almost anything to pursue, often with little or no narrative explanation as to why it is considered so desirable. A MacGuffin, therefore, functions merely as a plot element that catches the viewers attention or drives the plot. In fact, the specific nature of the MacGuffin may be ambiguous, undefined, left open to interpretation or otherwise completely unimportant to the plot. Common examples are money, victory, survival, a source of power, a potential threat, a mysterious but highly desired item or object. The MacGuffin is common in film, especially thrillers. Usually the MacGuffin is the central focus of the film in the first act, and then declines in importance as the struggles and motivations of characters play out. It may come back into play at the climax of the story, but sometimes the MacGuffin is actually forgotten by the end of the story.