At a place called The Only Inn in storm-damaged Glipwood, a Fang named Higgk cruelly pins the innkeeper, Joe Shooster, to the ground and interrogates him about the Igibys’ whereabouts. When Joe denies any knowledge of the family, Higgk strikes him and grabs Joe’s wife, Addie. Other Fangs encourage Higgk to bite her. As Higgk’s fangs drip venom onto Addie’s clothing, she faints. Hearing a whistling teapot, Addie begins to revive, and Joe is suddenly inspired to bargain for their lives by offering Addie’s excellent cooking to the Fangs. When Addie revives, she invents a dish that she calls critternose casserole. Higgk releases her, demanding the meal by sundown.

Instead of gathering ingredients for the meal, Joe slips upstairs to room eight and moves a chest of drawers aside to reveal a secret door. Inside this hideout, he tends to a wounded Oskar N. Reteep, the kind man who runs the Glipwood bookshop. Oskar has been hiding there for weeks, ever since Joe found him in the aftermath of a deadly struggle in On the Edge of the Dark Sea of Darkness, “when Podo and the Igibys fled to Anklejelly Manor to escape the hundreds of Fangs that had come for them” (11). Now, Oskar tries to warn Joe about Zouzab. (Zouzab is his bookshop employee, a diminutive “ridgerunner” who climbs the bookshelves; he betrayed the Igibys to the Fangs in the previous novel). However, before Oskar can convey this information, he is overcome by coughing and falls asleep. Joe recalls finding Oskar wounded after a great battle and contemplates his memories of later witnessing the Fangs killing their neighbor, Shaggy Bandibund.

After leaving the secret room, Joe sees Zouzab at the window. Remembering Oskar’s half-articulated warning and sensing a sinister air about Zouzab, Joe grows suspicious and lies about Oskar’s location. Zouzab stares silently before leaving. A loud noise erupts from Oskar’s room. Zouzab’s head reappears at the window, but Joe shrugs it off, and the ridgerunner departs.

The day after the Igiby family decides to leave, Janner and Tink’s excitement about the journey fades when they are assigned to complete chores while the adults make plans. That evening, Nia and Podo study a map and plot their route to the Ice Prairies. They plan to travel west around Torrboro, then across the Mighty River Blapp to find a breach in the Barrier (a wall that Gnag the Nameless, the leader of the Fangs, built along the Stony Mountains to prevent northward escapes). Podo expresses his mistrust of Artham’s ability to guide them, and the adults decide that they need 30 days’ worth of provisions.

Meanwhile, at The Only Inn, Oskar worries when Joe and Addie do not visit all day. Suddenly, he hears screams that sound like Addie’s, followed by Fang snarls. Despite his wound, Oskar forces himself from bed and opens the secret door. From the window, he sees a new, more menacing Black Carriage (the vehicle that the Fangs use to kidnap children from various towns). This new Black Carriage has multiple coffin-like compartments. He watches in horror as Fangs force Joe and Addie into the compartments and drive away.

Oskar overhears two Fangs discussing their plans. A ridgerunner has told them that the Igibys are hiding in a tree house in the forest. The Fangs plan to move into the forest the next morning to capture the family. Weakened, Oskar collapses.

The next morning, the first day of autumn, Artham returns carrying the carcass of a creature called a cave blat and warning that horned hounds are on his trail. Leeli’s dog Nugget chases one down and returns victorious. While the children study, Artham digs a hole to bury his journals. Nia calls Janner and Tink down to try on the packs that she has sewn. She then fills them with supplies, including food, tools, and weapons, and gives the boys a scrubbing and haircut. Janner sees a new maturity in his reflection, but Tink just makes silly faces.

Janner hears a strange human voice coming from the forest. The family listens as it grows closer, accompanied by snapping twigs. Then the mysterious visitor warns the Igibys to run because enemies are coming.

Oskar N. Reteep arrives on a donkey that he stole from the Fangs that morning, shouting warnings at the Igibys, and Janner is overjoyed to see his old mentor alive. Suddenly, the exhausted donkey collapses, sending Oskar flying. As the family frantically packs, Oskar warns that hundreds of Fangs and trolls are minutes behind him. Tink drops Artham’s journals from the window; Artham wraps them and places them in the hole. Nia buries them and disguises the spot with leaves.

A moaning growl echoes through the woods, and Oskar identifies the sound as the call of the pursuing trolls. Podo orders everyone to escape, telling Tink to ride with Leeli on Nugget. Zouzab suddenly appears in a tree, making the family aware of his betrayal. Before Podo can react, Artham screeches and leaps into the branches to chase the ridgerunner. The two disappear into the trees.

With their southern route blocked, the family flees north. Oskar mentions a bridge ahead. Nia gives Janner Artham’s satchel for the donkey, and when Janner asks about their supply of healing water, she says she does not know where it is but that Artham had it. Podo announces that they cannot wait for Artham. Fangs emerge from the trees, and Podo leads the family deeper into the forest at a run.

The family runs north through increasingly steep terrain, pursued by many Fangs and three trolls. Janner is overcome with fear because the smell of the Fangs triggers his memories of past encounters. When Oskar collapses from his wound, Podo and Janner lift him onto the donkey. A painted, collared hound suddenly attacks. Tink freezes, but when Podo command shim to shoot it, he obeys. Two more hounds appear, but Artham suddenly swoops down from the trees, kills them, and vanishes, causing the Fangs to hesitate.

Podo leads them down into a deep, tree-choked gully, but the donkey refuses to descend, its nostrils flaring at something below. Despite its resistance, the family descends into the gully, although if Janner had thought to recall his studies from Pembrick’s Creaturepedia, he would have advised his family to avoid the area at all costs.

A footnote at the bottom of the page reads:

Avoid the gullies and sinkholes of Glipwood Forest at all costs. It is commonly known that the gargan rockroach sets its trap in such places. […] The sweet scent emanated by the female gargan rockroach sends some animals into a temperbolic trance and draws them irresistibly to the waiting rockroach. (29)

Leeli’s voice briefly coaxes the donkey forward, but a troll appears above, frightening it. Peet stands defiantly before the Fang army, creating a diversion. Podo and Janner abandon the donkey and lift Oskar down into the gully. Before rejoining the others, Janner grabs Artham’s satchel, finds the flask of water from the First Well inside, and tucks it into his pocket.

At the gully bottom, Nugget stands in a trance. Tink screams as a toothy cow emerges from the brushy floor and clamps its jaws on his foot. The commotion revives Nugget, who pounces on the unstable floor. Suddenly, the branched ceiling collapses, plunging Janner, Tink, Leeli, Podo, and Nugget into a gargan rockroach’s den, which is filled with other monsters such as toothy cows, cave blats, a wounded horned hound, and a quill diggle; all of these creatures have been dazed by the rockroach’s scent.

Podo tells the boys to draw their swords slowly. The horned hound rouses and is pricked by the quill diggle, sparking a fight among the drugged animals. Podo instructs the boys to cut a hole in the ceiling for Nugget to escape, then jumps into the fray as a diversion.

Janner yells at Tink to cut the hole, snapping that if Tink is to be a king, then he should act like one. Tink freezes, hurt by his brother’s words, then sprints to obey. Seeing Tink’s brief moment of hesitation, Janner feels a surge of contempt for his brother. Tink cuts a hole, allowing Janner to push Nugget and Leeli through to safety. Artham leaps through the opening into the den.

Podo screams as the massive gargan rockroach emerges and swallows a toothy cow whole.

The enormous gargan rockroach consumes a toothy cow, then devours the horned hound. Artham lands in the den as the creature turns its attention to him. Podo’s sword bounces uselessly off its armored leg. Janner ignores Podo’s order to flee and attacks the rockroach to save Artham. His sword also fails to penetrate the armor, and the creature knocks him across the den.

As the rockroach advances on Janner, a troll reaches through the ceiling hole and captures Artham. Lying on the floor, Janner feels the flask of water from the First Well in his pocket. He throws it into the rockroach’s open mouth. The magical water causes the creature to reel back as steam pours from its mouth.

Podo drags Janner out through the hole and up to the gully’s edge. They emerge to find the entire Fang army, including four trolls, across the gully. One troll holds a captive Artham while Zouzab and another ridgerunner sit on a troll’s shoulder. A Fang commander threatens to have the troll kill Artham.

The Fang commander threatens Artham’s life to force the family to surrender. Leeli orders them to release Artham, and Zouzab mocks her role as the Song Maiden of Anniera, causing the Fangs to snarl. Janner realizes that the Fangs want to take him and the other two alive, so he tells Podo and Nia to hide behind him and his siblings. As the children and Nugget form a protective line, the Fang commander laughs, pointing out that they are trapped.

Tink notices steam rising from the gully as the gargan rockroach grows. Janner bluffs, telling the Fangs that they are leaving. Oskar, now awake, randomly mentions a place called Miller’s Bridge, prompting Janner to recall a page from a history book. Podo chides Oskar for his random comments, and as the family backs away, the Fang commander shouts an order. The troll holding Artham withdraws, and the Fangs charge into the gully.

The now-enormous gargan rockroach erupts from the gully and attacks the Fang army, creating chaos. The family flees north toward the sound of the river. They reach the banks of the Mighty River Blapp, a torrent of impassable whitewater.

Trapped before the impassable river, the family debates options. Oskar is near collapse. Podo, expressing deep fear of the sea, suggests surrendering in order to protect the children. Leeli counters that they must not surrender, citing their late father’s bravery. Spurred by Oskar and Leeli, Podo reluctantly agrees to head east toward Fingap Falls in search of the legendary Miller’s Bridge.

As they make their way along the treacherous, rocky riverbank, a troll throws a boulder at them, and Fangs appear on the ridge above, firing arrows. Tink stops to study the rock face, and this pause angers Janner, who thinks that Tink is dawdling. The Fangs and trolls descend behind them, but the trolls are attacked by daggerfish in the shallows.

The family arrives at the brink of Fingap Falls and sees the Dark Sea of Darkness far below, but there is no bridge. Trapped between the falls, the cliffs, and the advancing Fang army, Nia confirms that if a bridge ever existed, it is gone now.

Janner confronts Tink for stopping earlier. In reply, Tink kicks away loose stones, exposing a hidden, man-made step carved into the rock. Seeing stairs leading down the cliff face, Janner apologizes. The family descends the narrow, misty stairs, which end at a wide gap with water rushing through. Fangs appear on the stairs behind them, and Podo turns to fight, holding them at the narrow pass.

Tink jumps across successfully, then Nugget leaps with Leeli. Nia attempts the jump but falls short; the rapids pull her sideways until Nugget lifts her out by her blouse.

Janner struggles with whether to flee or fight. Recalling his duty as Throne Warden and remembering that Artham was once Throne Warden to his father, Janner is filled with resolve. He arranges for Nugget to carry the wounded Oskar across. Podo tells Janner to escape while he holds off the Fangs, but Janner steps past his grandfather and raises his sword to fight beside him.

The Fangs suddenly retreat. Janner and Podo cross the gap, with Nugget carrying Podo. As they continue, they hear a troll running down the stairs behind them. The mist clears, revealing the vast Dark Sea far below, along with the legendary Miller’s Bridge: a series of narrow stone spans connecting the giant rock towers that stand in the waterfall itself. The ancient structure hints at a greater civilization.

A troll appears on a boulder above, having bypassed the stairs. The family sprints to the first tower as the troll leaps down. A second troll arrives, and both monsters wait on the ledge while the Fangs cross the bridge in single file. Podo stares at the sea with a defiant, trembling expression.

Podo orders Janner and Tink to provide covering fire while he, Nia, Leeli, Oskar, and Nugget cross to the next tower. Tink looses an arrow at the approaching Fangs.