(Detailed) plot overview: As "Crooked Kingdom" unfolds, Ketterdam's tranquility is shattered when Shu Han soldiers, enhanced by Grisha magic, kidnap Ravkan Grisha Retvenko from the harbor. Concurrently, Kaz and Wylan infiltrate the residence of Van Eck's attorney, unearthing crucial information to rescue their comrade, Inej. However, Inej's escape efforts are thwarted, and she faces the grim possibility of crippling injury, compelling her to grapple with doubts about her worth to Kaz beyond her utility.
Jesper's predicament deepens as his father, Colm Fahey, arrives, seeking answers about the misused loan meant for Jesper's education. The Dregs concoct a story of deception and pledge to recover the lost funds, all while orchestrating a daring swap of Van Eck's pregnant wife for Inej. The exchange triggers Van Eck's wrath, unleashing the city's law enforcement on the Dregs. Despite the turmoil, Kaz and Inej manage to elude capture, but their allies face a fierce confrontation with the same Grisha-hunting Shu soldiers who seized Retvenko.
Back at their sanctuary, Kaz reveals a daring strategy to dismantle Van Eck's fortune by targeting his sugar reserves. Inej, initially hesitant, commits to the plan only after Kaz vows to ensure the safety of Ketterdam's Grisha by escorting them to Ravka. As Wylan uncovers the shocking truth about his presumed-dead mother, the Dregs find themselves in the crosshairs of a perilous alliance between Van Eck and Pekka Rollins, a mobster intertwined with Kaz's troubled past. As Rollins's forces besiege their hideout, Matthias's tactical acumen and Jesper's Grisha abilities become their lifeline.
But, even as Rollins dispatches the lethal Dunyasha to thwart Inej, Nina unexpectedly somehow summons an undead army to their rescue. In a high-stakes game of cat and mouse at Van Eck's mansion, Kaz and Wylan narrowly evade capture, but their carefully laid plans crumble. As the city's criminal factions and law enforcement converge in a relentless manhunt, Kaz, ever the strategist, devises a daring countermove.
Kaz's intricate scheme unfolds with Kuwei's public auction and Jesper's father's deception of the Kerch Merchant Council. As Kaz reclaims leadership of the Dregs, a pre-auction gambit involving a morgue sample and a staged confrontation with Wylan sets the stage for their audacious plan. Amid the auction, the Grisha refugees, masquerading as the enigmatic Council of Tides, disrupt the event, exposing Van Eck's illicit dealings. The resulting scandal topples Van Eck, paving the way for Wylan to inherit his empire. Meanwhile, Kaz cunningly orchestrates Rollins's hasty retreat from the city by instilling the fear of a buried alive son.
Concurrently, Nina weaponizes the morgue sample to incite panic over a fictitious plague. In the chaos, Jesper's marksmanship plays a pivotal role in staging Kuwei's "death," though a tragic turn sees Matthias fatally shot amidst a tense standoff, leaving Nina with a heart-wrenching promise to uphold.
As the crew part ways, embarking on their respective journeys, Kaz secures Kuwei's safety and asserts his influence over the real Council of Tides. His final acts of cunning ensure Inej's family reunion and equip her with a formidable vessel, symbolizing their united front against Ketterdam's injustices. The book ends with Inej's menacing encounter with Rollins, cementing her and Kaz's unwavering resolve to cleanse the city's corruption.
