(Night Island is a 21,000-word YA novella. Recommended for readers in Grade 9 and above.)
Welcome to Mary Island, aka "Night Island."
Here, the sands are soft and white, the beaches pristine. The locals aren't so friendly, but at least they won't crash your party.
But be sure to leave before night comes; don't stay the night. Because if you do, you may not live to see tomorrow . . .