|“||We are all of Erdas, united.||”|
–Book Quote, (from Chapter 15: Glue)
Conor, Abeke, Meilin, and Rollan are young heroes who stopped an unstoppable monster. They are Greencloaks - guardians chosen by every nation in Erdas - and together with their powerful spirit animals, they fight to protect their world.
But in the ashes of this destruction, there are some who ask: Are the Greencloaks to blame? The young heroes are shocked to find themselves on trial, judged by a council of the world's leaders. Then the unthinkable happens. The council is attacked from within - by Greencloaks - and an important leader lies slain.
In the blink of an eye, Erdas's saviors become wanted fugitives. Someone is trying to frame them as traitors, but why? As the four friends race to uncover this mystery, only one thing is clear.
The war is far from over.
The Four Fallen are late for their meeting at The Citadel because Jhi got sick eating a lot of bamboo. They are stopped at the entrance by Oathbound guards, one of whom is Brunhild the Merry. Brunhild attacks, and the young Greencloaks defend. Brunhild presumptuously releases her Stone Viper, but it is nowhere to be seen. Suddenly, Princess Song arrives and calls off the guards. She says that spirit animals must be in passive state, so Conor and Abeke go inside after calling back their spirit animals, while Meilin and Rollan stay outside and try to convince Essix to go into passive state. Meanwhile, Princess Song tries to get them all separate rooms in their country's separate wings, but Conor and Abeke override that.
Abeke and Conor go to their room (which is falling apart) and Conor takes a nap that comes with another nightmare of The Wyrm. Abeke reassures him once he wakes up, and he calms down. He asks her about her feelings about Shane, which she describes as 'complicated'. Then, Rollan and Meilin enter into the room, and are none too happy about the condition of it.
Meilin meets Princess Song again (who she was childhood acquaintances with) and they eat spiced buns and hot tea. She grabs two buns for her friends, and soon after, the emperor walks in. She drops one of the buns accidentally as she bows. After he leaves, she grabs it and goes back to her room. Merlin hands each of her friends a spiced bun. Rollan is very suspicious of his bun, as it is very gritty.
They go to the meeting they were called for, and realizes that it is more of a trial than conference. Suddenly, six Greencloaks burst in and start attacking. They kill the emperor, and leave. The Oathbound start to arrest the Greencloaks in the room. Lenori and the rest of the Greencloaks go peacefully, while Olvan and the Four escape. Olvan gives them an amulet called the Heart of the Land. He gets bitten by Brunhild's stone viper and becomes petrified, but not before giving the four directions out of the Citadel, which they fail terribly at remembering. Just then, a woman appears. Her name is Anka, and leads them through a camouflaged door and out of the Citadel. They run and rest and run again, but during the rest, Anka tells them what the Heart is and what to do with it. It was from Amaya, and gives power to the wielder. There are three more amulets, each wielded by four heroes from the past.
Later, the next day, the group gets themselves trapped in spiderwebs and caught by Wikam the Just.
Meanwhile, in the new Redcloak base; a tower on a beach that looks like a torch, Stead summons Worthy and put him to a task to follow the Four Fallen and help them find a rock (the Heart of the Land from Amaya) a circle ( The Dragon's Eye from Zhong), a claw ( The Wildcat's Claw from Eura) and another thing, probably from Nilo and related to a hammerkop. Worthy agrees to the task.
The Greencloaks escape from the spiderwebs and runs for it. They board a ship to Amaya; during the ride Conor stops having Wyrm-related dreams.
In Amaya, Abeke catches Worthy following them. The Greencloaks let him join them after some arguing. Rollan and the others have a short spat about if they should or should not put their cloaks away. Worthy interrupts with a comment about how Tarik's old cloak and Rollan's current cloak is basically rags. Abeke, Conor, and Meilin bury their cloaks into a shallow hole. Rollan puts his cloak at the bottom of the groceries bag, and he and Conor go shopping in Concorba. They meant at first to go to Monte's shop, but find out that it got shut down and he got taken away by the Oathbound. So, they but food, medical supplies, arrows, and a fur cloak somewhere else. The two stow away the supplies in a nearby alley and walk into Rollan's mom, Aidana's, school. Ngozi tells the two to sit down or they'll be in trouble, as Aidana is a tough teacher. Sora disagrees, saying that Aidana is a wonderful teacher. Aidana turns around, and gets mock-mad at her son. They hug, and all too soon, their reunion is cut short as Jean-Luc says that the Oathbound are at the door. The two Greencloaks escape, but are ambushed, and their only weapon is a short dagger or Rollan's. Worthy jumps in the fight, and later, so do Aidana and the three aforementioned students. Turns out, Aidana's school not only teaches math and reading, but also fighting with spirit animals. Conor, Rollan, and Worthy escape. After that skirmish, Rollan and Conor are more friendly towards Worthy. They grab the supplies and run out of Concorba back to their camp.
At the camp, Meilin had been teaching Anka fighting forms when the boys return. Hearing a noise, Abeke nocks an arrow, then puts it down after realizing it was only Rollan, Conor, and Worthy. They head out again, traveling hard, barely sleeping, and not kindling any fires. Whenever Essix cries a warning, Anka hides them all.
Rollan and Meilin walk towards a waterfall he saw, away from the camp. They share a kiss, and then hear sounds of battle. They head back to camp, and realize that the Oathbound have ambushed them. They retreat, and run. Rollan uses Essix's eyes, and realizes that the Oathbounds did not pursue because they were driving them towards an Oathbound army. Conor tells them of his dream of being on a tower, when big wave hits him. The others think that it is the 'island' in a lake in the distance: the Heart of the Land. The 'island' is more of a cliff, but the Rollan, Meilin, Conor, and Abeke scale it in a storm while Anka and Worthy guard the only way to the island without a boat. Once they are on the island, Rollan activates something by placing the stone onto a dip in the ground, and Kikimi, a spirit, speaks to them. She was the summoner of the Gila monster, and reveals the Heart. The stone turns out to be an amber rock on a chain with a Gila monster shape inside. It is an amulet.
The four friends climb back down the cliffside to meet a losing battle. Rollan uses the amulet to save the Greencloaks and Worthy, but they are almost forced to surrender when Worthy yowls for reinforcements. About twelve Redcloaks come, and Rollan makes a tunnel for him, the other Greencloaks, and Worthy to crawl into. The tunnel collapses behind them as the way is burrowed before them. Meilin feels a soft and furry rope touch her cheek twice, so she grabs it and yanks. Worthy yowls, and Meilin has a suspicion on what it is.
The ground spits them out somewhere, and they all get up and one point or another. Worthy suddenly feels the pain from four wounds at once, and thinks he is dying (of relatively shallow cuts). Jhi gives him healing from panda spit, and he feels better. The other five talk about what happened at the top of the cliff while Anka and Worthy were guarding the small sand bridge. Finally, Worthy gets up, puts on a spare mask, and tells them about the Wildcat's Claw, a legendary sword from Eura.</div></div>
- Sora, Ngozi, and Jean-Luc first appear in Chapter 13 : Ambush. These characters were made by the Spirit Animals community via polls on the Scholastic Spirit Animals forums.
- On the cover, Heart of the Land is the only book so far that shows Essix with a speckled belly.