Lost City (Dinotopia, #4)

Andrew, the son of a Dinotopian innkeeper, makes a strange discovery one night when a hooded dinosaur leads him and two friends to a remote, sealed-off city. When they begin to explore the forbidden area, the trio are thrust into a dangerous adventure--one they can survive only if they can put aside their chronic rivalries and come to understand the lost race of TroÜdons, who have existed there in seclusion for centuries.