The Pearls of Lutra begins just outside Redwall Abbey, where a young hogmaid named Tansy has been sent to gather herbs for Sister Cicely, with her young friend, Arven, keeping her company. A couple of hours after Tansy leaves the Abbey, the weather takes a turn for the worse, and it begins to rain. The two friends take shelter in a nearby cave, and Tansy soon finds herself looking for Arven, after the young squirrel runs off. Meanwhile, on Sampetra Isle, Emperor Ublaz reigns, holding the title of Mad Eyes, because of his hypnotic stare.
Mad Eyes commands hundreds of tropical lizards, and trident rats.
He has already murdered the otter tribe, Holt Lutra, to gain them. Yet the rat he sent to fetch the pearls has not returned. His one great mistake was taking Grath Longfletch, daughter of the tribe leader, for dead. For she is not dead. Grath Longfletch will be known for season's to come, killing searats like a madbeast, with her reknowned green-flighted arrows.