From the introduction: Forgotten Bones is intended for four characters with an average party level (APL) of 5. Characters who complete this adventure should earn enough experience to reach halfway to 6th-level. The characters are invited to a fancy soiree. Unbeknownst to them, however, the night will not go as planned. This campaign takes place in Arden, although it can be set in your own world. Any party composition should be able to finish the adventure with intelligent play.