Your story in one or two sentences: who wants what, what stands in the way, and what's at stake.
A logline compresses a whole story into a sentence or two — a described (not named) protagonist, a concrete goal, the obstacle pushing back, and the cost of failure. It's the first thing industry readers see and the fastest test of whether a story's engine actually turns over.
A logline that won't come clean is usually diagnosing the draft, not the sentence: if the goal or stakes are vague in twenty-five words, they're probably vague at ninety pages too.
Go deeper: How to Write a Logline
In One More Draft: Logline Arena — free coaching