From the introduction: Jungle Heat (Vol I): They Come at Night 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. A famed explorer sought out a lost island and now the characters must go rescue him. 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.