. "Return to the Underworld is an unofficial sequel to Kenneth Oppel's novel Firewing."@en . "''[[w:c:silverwing:Firewing"@en . "2011-04-06"^^ . "2011-04-16"^^ . "Author"@en . "Cama Zotz has the Upper World in his sights. The northern bats must gather together their old alliances to thwart him. The living and the dead will clash in one final battle that will determine the future of both worlds."@en . . "Previous Story"@en . "Return to the Underworld is an unofficial sequel to Kenneth Oppel's novel Firewing."@en . "2011-04-10"^^ . . "Date completed"@en . . "Return to the Underworld"@en . "Date began"@en . "Date published"@en . "Return to the Underworld"@en . .