Grim Tales: The Curse of the Doubloons by Linda Demeulemeester
Free selection in the Amazon kindle e-book store
This is a short story based on the Grim Hill characters, which I haven't read. It did feel a little like I was missing some of the big picture. It didn't read like I needed to have read the books, but I could tell there were bigger stories for these characters of which I was unaware.
Cat and her little sister, Sookie go on a field trip to New Orleans, and somehow when trying to make it to through a museum tour, leaving some time to go on a swamp boat tour. Instead, they, along with a group of their school friends, wind up on a pirate ghost ship and need to find a way off before they are stuck there forever.
Interesting and well written, this was a pretty good introduction to the Grim HIll world. I would definitely be interested in seeing what the full length books in the series are about.