From the publisher's web site:
Tell your own fantastic tales of brave heroes and daring adventure!
Once Upon a Time is the award-winning storytelling card game that encourages creativity and collaborative play. One player is the Storyteller, and begins telling a story using the fairytale elements on her Story cards, guiding the plot toward her Ending Card. The other players use their own cards to interrupt her and become the new Storyteller. The winner is the first player to use all her Story Cards and play her Ending Card. The object of the game, though, isn't just to win, but to have fun telling a story together.
Once Upon a Time was named to GAMES Magazine's Best Family Card Game section in 1997.