I was introduced to this game many years ago, but it wasn’t until a few months ago that I managed to get my hands on a copy of my own.
To describe it as simply as possible. Each player is dealt a hand of cards. Each card has a different fairy tale story element on it (A Prince, a castle, long journey, a talking animal). The active player tells a story, playing the cards as they are incorporated into the story. Other players can take over the story if the storyteller mentions something they have a card for. Each player is trying to conclude the story in a way that matches the specific ending they have secretly been given.
It’s tremendous good fun, and it’s a great way to get non-improvisers telling stories, as well as good storytelling practice for improvisers.
Game designer James Wallis has another game which sounds even better; The Extraordinary Adventures of Baron Munchausen.