The Pearls of Lutra (published as Pearls of Lutra in the US) is a fantasy novel by Brian Jacques, published in 1996. It is the ninth book published and eleventh chronologically in the Redwall series.
Plot summary
When gathering herbs near the quarry in Mossflower Woods, the young Redwallers Tansy and Arven come across a mysterious skeleton among the rocks. They are disoriented in a rainstorm and after failing to return to the abbey before the breaking of the storm are rescued by Martin II, son of Mattimeo and grandson of Matthias. Tansy quickly leads curious Redwallers back to the quarry to examine the mysterious skeleton, and along the way, they meet two travellers: the irrepressible hare Cleckstarr Lepus Montisle and his owl friend Gerul.
Meanwhile, far across the western sea on the tropical isle of Sampetra, trouble is brewing. Ublaz Mad-Eyes, a large, sinewy pine marten with a hypnotic stare, gathers an army of barbaric monitor lizards and trident-wielding searats. The stoat captain Conva is sent out to retrieve the Tears of All Oceans, six perfectly spherical rose-pink pearls, but after murdering the Holt Lutra who owned the pearls, the Tears are stolen by the weasel Graylunk, who flees into Mossflower Woods. Conva tracks him to Redwall Abbey, where Graylunk takes refuge, before returning to Sampetra.
Ublaz is not pleased and murders Conva. He then sends out an elite force of monitor lizards, headed by their general Lask Frildur, to Mossflower to retrieve the pearls. They are escorted by the ferret captain Romsca and her crew.
However, the daughter of the Lutra chieftain is not dead. Far away on the western shores, Grath Longfletch, a strong female otter, was at the gates of the Dark Forest before being found by a pair of bankvoles, who nurse her back to health. The otter fashions a powerful bow and a quiver of green-fletched arrows, with which she planned on wreaking her revenge. She eliminates a longboat-crew of searats and then takes their boat southward into Mossflower, where she hopes to find the corsairs that slew her family.
Presently, Conva's brother Barranca discovers that Ublaz has killed his brother, and he begins hatching a plan to overthrow the pine marten and take the island for himself. With the fearsome Lask and his lizards gone to Mossflower, Barranca decides to seize his chance.
Back at Redwall, the old bankvole recorder Rollo determines that the skeleton in the quarry was Graylunk. He had become gravely injured in a fight with the weasel Flairnose, whom he killed, over the pearls before seeking safety at Redwall. There he befriended an old squirrel called Sister Fermald before he went off to die in the woods. Fermald, a clever, though senile old beast, had expertly hidden the pearls throughout the abbey before passing away several seasons ago. Tansy, Rollo, and Martin II, along with the hedgehog maid's friends Craklyn the squirrel and Piknim the mouse, begin a search for the six exquisite pearls. The Dibbun Arven and his two partners in crime, the moles Diggum and Gurrbowl, occasionally help in the search.
When Abbot Durral takes young Viola Bankvole for a stroll in Mossflower Woods, they are captured by Lask and his troops. Lask binds the Abbot and the bankvole and attempts to ransom them for the pearls at Redwall. However, the pearls have not yet been found, and Lask and his lizards take the two Redwallers back to their ship to be captives at Sampetra.
Martin, Clecky, Gerul, and the Skipper of Otters pursue the lizards through Mossflower, slaying several but failing to rescue the captives. Gerul and Skipper become wounded and are sent back to the Abbey, but the others chase the lizards to the western shore. There, they meet up with the GUOSSSIM and Grath Longfletch, who had caught sight of Romsca's ship, the Waveworm, and attempted to pick off some of the vermin. Durral manages to help Viola get to safety on the shore, but the ship departs before he can escape. Viola is sent back to Redwall with two shrews to guide her, and Grath, Clecky, Martin, and the Log-a-Log's two sons use discarded vermin boats to form the Freebeast, a double-outrigger vessel in which they pursue Lask to Sampetra. Viola, who has sneaked aboard, also ends up coming along.