While looking at agents and publishers, you might come across the term high-concept.
A high-concept novel has a plotline (and possibly thematic elements) that can be summed up in a single line. It’s going to have a broad appeal (read: mainstream or commercial) and will offer something unique.
So it’s a tricky interplay of immediately recognizable, familiar enough in terms of a specific, clear market, while also being unique enough to spark interest with a broad number of readers.
If you need help with your tagline (that tricky single sentence that pitches your book, high-concept or not), feel free to visit Writer’s Resource’s website for information on assistance with your tagline.