The Illyrian Adventure by Lloyd Alexander

Lloyd Alexander has done it again, writing yet another action-packed adventurous book! In a land of two repelling forces, Vesper Holly with only her guardian to help and protect her must uncover the old feudal history of Illyria. During Vesper's stay, she befriends both side's leader while she is stalked by someone else. Having a close shave with an assassin when she first arrives, Vesper embarks on her dangerous yet exciting quest to find the legendary treasure and the army of magical warriors. Audrey C.