Pearls of Lutra (Redwall, #9)

The Tears of All Oceans are missing. Six magnificent rose-colored pearls, which inspire passion and greed in all who see them, have been stolen and passed from hand to hand, leaving a cryptic trail of death and deception in their wake. And now Ublaz Mad Eyes, the evil emperor of a tropical isle, is determined to let no one stand in the way of his desperate attempt to claim the pearls as his own. At Redwall Abbey, a young hedgehog maid, Tansy, is equally determined to find the pearls first, with the help of her friends. And she must succeed, for the life of one she holds dear is in great danger. . . .