Gregor and the Marks of Secret

Its place in The Underland Chronicles

Gregor and the Marks of Secret is book 4 in the The Underland Chronicles series. It follows Gregor and the Curse of the Warmbloods. It is followed by Gregor and the Code of Claw. See the full The Underland Chronicles reading order.

Before The Hunger Games, Suzanne Collins wrote this five-book middle-grade series about Gregor, an eleven-year-old New Yorker who falls through a grate in his apartment building's laundry room and lands in the Underland -- a vast subterranean world beneath New York City populated by humans who have adapted to life underground, along with giant, sentient versions of bats, rats, cockroaches, and spiders, all bound by a fragile web of alliances and old grudges. Gregor arrives clutching his baby sister Boots and is…