The trio of intrepid explorers introduced in Bartlett and the Ice Voyage (2003) again deploys generous measures of ingenuity, perseverance, and desperation in pursuit of a seemingly impossible task. Emerging from months spent mapping a huge cave system, Bartlett, his massive sidekick Jacques Le Grand, and lively, ingenuous young Gozo find themselves in an unknown country, caught up in a bitter feud over a kidnapped prince. Being a dead ringer for the royal lad, Gozo is instantly seized by the land’s royal couple—so in order to free him, Bartlett must first track down the elusive race of cavern dwellers who are holding the real prince, then satisfy their leader’s demand that he find a way to bring the sun itself underground. Illustrated with frequent, diminutive ink-and-wash vignettes and well-stocked with characters foolish or wise—or interesting combinations of the two—this leisurely but engaging import will please fans of faintly offbeat adventure tales. (Fiction. 11-13)