MacGuffin

In fiction, a MacGuffin (sometimes McGuffin or maguffin) is a plot device in the form of some goal, desired object, or other motivator that the protagonist pursues, often with little or no narrative explanation. The specific nature of a MacGuffin is typically unimportant to the overall plot. The most common type of MacGuffin is a person, place, or thing (such as money or an object of value). Other more abstract types include victory, glory, survival, power, love, or some unexplained driving force.

The MacGuffin technique is common in films, especially thrillers. Usually the MacGuffin is the central focus of the film in the first act, and thereafter declines in importance. It may reappear at the climax of the story but sometimes is actually forgotten by the end of the story. Multiple MacGuffins are sometimes derisively identified as plot coupons.

As noted by Marjory Ward, "the use of a MacGuffin as a plot device far predates this modern nickname. For example, the Holy Grail of Arthurian Legend could be considered an early MacGuffin, doing for the plot all that a good MacGuffin should do".

Objects that serve as MacGuffins are familiar in narrative fiction. For example, a small statuette provides both the eponymous title and the motive for intrigue in The Maltese Falcon. The name "MacGuffin" was coined by the English screenwriter Angus MacPhail, although it was popularised by Alfred Hitchcock in the 1930s, but the concept pre-dates the term. The World War I–era actress Pearl White used weenie to identify whatever object (a roll of film, a rare coin, expensive diamonds, etc.) impelled the heroes, and often the villains as well, to pursue each other through the convoluted plots of The Perils of Pauline and the other silent film serials in which she starred.

...
Wikipedia