In many news stories, the essential facts of a story are included in the lede, the first sentence or two of a story. Good ledes try to answer who, what, when, where, why, and how as quickly as possible.
The nut graf, which often will start in the third, fourth, or fifth paragraph, will explain any additional context for why the story is important. For example, if the news story concerns a candidate for an upcoming election, the nut graf will state when the election is and may expand upon issues of the election. If the new story is part of an ongoing story, the nut graf will likely summarize other recent events related to the newest revelations.