Gregor and the Curse of the Warmbloods (underland Chronicles, #3)

The third installment of Suzanne Collins's Underland Chronicles finds eleven-year-old Gregor back in New York City, months after his second journey to the Underland, a vast world beneath the city inhabited by giant talking rats, bats, cockroaches, mice, and a civilization of pale-skinned humans called Regalians. Gregor secretly studies "The Prophecy of Blood," written backward and slipped to him by Nerissa, the frail, vision-prone queen of Regalia. The poem warns of a bloodborne plague that will devastate all warmblooded creatures and calls for a warrior and a princess to come from above to find a cure. Meanwhile, Gregor is tormented by the unknown fates of friends who went missing on his previous quest: Luxa, the young queen of Regalia; her bat Aurora; and the cockroach Temp.

While helping his elderly neighbor Mrs. Cormaci with laundry, Gregor discovers a scroll wedged in the laundry room grate, a gateway to the Underland. The message from Vikus, Luxa's grandfather and a senior Regalian leader, warns urgently that the prophecy is upon them. Gregor and his father travel to Central Park, where they encounter not Vikus but Ripred, a scarred, cunning rat and Gregor's reluctant ally. Ripred reveals that a plague called "The Curse of the Warmbloods" is killing rats and spreading to bats. Ares, Gregor's bonded bat and sworn protector, is gravely ill. Ripred claims Gregor and his toddler sister Boots need only attend a brief meeting, but he threatens that rats will invade their apartment if they refuse.

Gregor's mother refuses to let them go. That night, hundreds of rats swarm inside the apartment walls and block the building's entrance. She relents but insists on accompanying them. Gregor's eight-year-old sister Lizzie stays behind with their father and grandmother. At midnight, Nike, a Regalian bat, arrives at the grate to carry them down to the Underland.

In Regalia, Doctor Neveeve, the city's foremost plague physician, tests their blood and pronounces them plague-free, a surprising result for Gregor given his exposure to Ares's infected blood on the previous quest. Gregor sneaks to the hospital and finds Ares behind a glass quarantine wall, his fur gone, his body covered in oozing purple bumps. The soldier Mareth warns Gregor that Ripred likely lied: a quest for the cure is almost certainly expected.

A meeting convenes with humans, bats, cockroaches, and rats. Neveeve presents old records describing a plant called starshade that cured similar plagues centuries ago, growing only in the Vineyard of Eyes, a deadly and feared valley. Tensions erupt between the humans and rats over the humans' withholding of yellow powder that kills plague-carrying fleas. A plague-stricken bat crashes into the arena and dies; when soldiers torch the body, swarms of fleas leap from the corpse. Everyone is evacuated and coated in flea powder, but Gregor discovers a red bite swelling on his mother's hand. She is immediately quarantined. Neveeve privately tells Gregor she could die within two weeks.

Devastated, Gregor vows to find the cure. The quest party includes Gregor and Boots, Nike, the military commander Solovet and her bat, Ripred with rats Mange and Lapblood, and Temp. At the Arch of Tantalus, a foreboding rock formation at the jungle's edge, their guide appears: Hamnet, Vikus and Solovet's son and Luxa's uncle, presumed dead for a decade. He brings his young son Hazard, a Halflander born to an Underlander father and an Overlander, or surface-world, mother, and a colossal lizard named Frill. Solovet is bitter that Hamnet abandoned Regalia; Hamnet refuses to let her join. He agrees to guide them only after Hazard persuades him, and Solovet departs with Vikus.

The jungle is sweltering, dense, and lethal. When poison arrow frogs surround Boots, Lapblood saves the toddler by flipping her away, and Gregor's rager instinct, a natural-born fighting ability he cannot control, activates involuntarily as he skewers a frog. Disaster compounds when Mange follows his nose to a sweet-smelling plant and is devoured by a carnivorous pod. Vines seize Gregor and Lapblood, but Ripred shreds the plants and saves them. Mange is dead, Nike's leg is broken, and the group's food and water are lost.

The party endures a harrowing march without supplies. When Ripred finally smells clean water, Gregor, Ripred, and Lapblood stumble into quicksand. Lapblood, overwhelmed by grief over Mange and her dying pups, gives up. Then Luxa appears at the bank with a group of mice, her clothes in rags and a scar on her face. She watches Gregor sink, believing he has allied with the rats, until Hamnet arrives and shames her into action. Gregor revives Lapblood's will to live by calling out the names of her surviving pups, Flyfur and Sixclaw.

Luxa explains she has been living with the mice since Aurora dislocated her wing. She rejoins the group. Around the lantern, Ripred reveals why Hamnet left Regalia: years earlier, Solovet ordered him to retake the Garden of the Hesperides, a fertile orchard gifted to the rats, by flooding the plain. The ancient dike collapsed, drowning hundreds of rats, humans, and bats, and killing Hamnet's bonded bat. He went mad and fled.

The party enters the Vineyard of Eyes and survives a corridor of silver flowers whose intoxicating scent induces euphoric disorientation. Beyond it, they find the starshade field and begin harvesting. Then hundreds of red ants flood in, shredding every plant. Gregor summons his rager ability, but the ants are overwhelming. The starshade is destroyed. Frill is killed. Hamnet is mortally wounded, and he dies after making Luxa promise that Hazard will be "anything but a warrior."

In the devastated field, Temp speaks the crucial insight: the Vineyard may not be where the plague originated, meaning the cure could exist elsewhere. Gregor suddenly connects details from Neveeve's lab: a plague container broke there while Ares was being treated for wounds, infecting him accidentally. This explains why Gregor, Luxa, and Aurora never contracted the plague despite close contact with Ares. Neveeve had both the plague and the cure all along. The prophecy's repeating stanza clicks into place: "Remedy and wrong entwine" refers to Neveeve, who embodies both the cure and the crime. The humans must look inward; the cure is in Regalia.

The party flies home. In the Regalian council chamber, Neveeve is presenting vials of an orange cure, reporting that Gregor's mother and Ares are improving. Luxa confronts her, and Neveeve admits Ares was accidentally infected in her lab and that she concealed the truth, insisting she was following orders to develop the plague as a weapon. Vikus orders her arrest. Luxa demands the first doses go to the rats, honoring her pledge to Ripred.

During Gregor's recovery, he learns Neveeve has been executed for treason. Solovet, Vikus's wife and head of the secret weapons committee that authorized the plague research, is confined and under investigation. Nerissa explains that without the quest revealing the truth, the humans would never have shared the cure with the rats, who would have attacked in desperation, triggering a war that destroyed all warmbloods. Gregor visits his mother in quarantine; she is weak but improving and makes him promise to take Boots home. Luxa tells Gregor his mother must stay underground for months until the plague fully leaves her blood, lest it spread to the surface world.

Vikus flies Gregor and Boots home. Gregor discovers his father's illness is relapsing and Lizzie is worrying about money. Overwhelmed, Gregor goes to Mrs. Cormaci's apartment for his Saturday job. She gives him sneakers for his birthday, which passed unnoticed in the jungle. Unable to carry the burden alone, Gregor asks Mrs. Cormaci if she can keep a secret, preparing to confide in her and seek the help his family needs.