A character is way down in the line of succession for some political office, to the point where it's reasonable to assume that they're never going to actually take it. Then everyone ahead of them dies or is otherwise disqualified. Usually this is either because a) some giant disaster occurs, or b) the character in question is evil and killing everyone ahead of them. It can also result from a Succession Crisis. Also contrast Offered the Crown, where the monarch is selected, and Succession Crisis, where ambiguity about who the rightful successor is causes problems.