The colour of her panties

"Preoccupied with helping Gwenny beat out her awful half-brother, Gobble, for chiefship of the goblin horde, Che Centaur and Jenny Elf, along with Gwenny, must find the fabulous egg in order to reach their goal."@en
"We See England, We See Xanth, We See Mels's UnderpanthIn fact, Gwenny Goblin, Che Centaur and Jenny Elf are just about the only creatures on Xanth who have been spared the sight of Mela Merwoman's undergarment -- preoccupied as they are with helping Gwenny beat out her awful half-brother Gobble for chiefship of the goblin horde. But first they must master space and thyme . . . and find the fabulous egg that sits between the Roc and the hard place. While Mela -- who would gladly relinquish her oft-viewed undies for a new husband -- joins the Adult Conspiracy . . . and quickly discovers the power of a perfect pair of panties!"
"Che Centaur and Jenny Elf help their friend, Gweny Goblin, to beat out her half-brother for chiefship of the goblin horde."