A plot Coupon is a term used for describing lack of plot etc. from books games etc. allowing the writer/ director to do basicly any thing that would normaly have been ruled out by the situation/ charicters/ personalities, often in an idiotic, improbable or unexplainable manner.

It can also be used in real life situations for unexpected bouts of luck.

(noun) A successful type of theft which results in an acceptable, impressive and rewarding payday for the protagonist.