Jennifer Maas TV Business Writer SPOILER ALERT: This article contains massive spoilers for Rebecca Yarros‘s best-selling fantasy novel “Fourth Wing” and its sequel “Iron Flame,” released Nov. 7. It could be a while before the “Fourth Wing” TV series that’s in the works at Amazon makes it to the screen, but with the release of the sequel novel titled “Iron Flame,” we have more than enough source material to begin anticipating the small-screen adaptation that’s set to cover all five planned books in the series.