The chapter opens with that Rin vs Ergo fight scene from the spoiler pages. It starts with Waver throwing advice to both sides, but as Rin continues to dominate the match with her combo of Gandr and Baji Quan covering all ranges, he switches to advising only Ergo. Rin's strategy is to create ropes from the Gandr's bullet holes. They talk about it after the fight, noting mainly how what made Rin's tactic difficult was the fact that Ergo's upper right Phantom Hand would cancel her formula on contact, but that was only on the upper right one, so Waver deduces that all 6 Phantom Hands have unique traits.
Next we have some quieter character moments for Rin and Ergo. Since chapter 1, Gray's narration was already using the word "puppy" to describe Ergo's personality, but this is shown better here, with him letting the kids play around with him and cut his hair. Waver finally questions why Rin's pirate crew is made only of children, and Rin answers that she just found a large group of orphans and felt like she had to take responsibility for them, because since they shoved themselves into her line of sight, they're now part of her world. Waver is slightly concerned about this answer because he once had a conversation with one of Luvia's butlers, the one that came to London accompanying Rin, and he talked a lot about heroes and justice, so Waver suspect he's being a weird influence on her. Waver asks if they are in a relationship and Rin denies it, but in a way that makes clear that she wishes they were. Rin compliments how well he understands his students, leading to Waver confessing he's planning to quit. Rin says it's a shame because she feels like he was born to teach, and asks to have a private conversation with Gray. In private, Rin tells Gray that she looks identical to someone she knows, and decides to talk a little about her Grail War.
At the same time, the kids are done cutting Ergo's hair, so he goes talk to Waver. Waver's mildly amused by how Ergo is nothing like the other red-haired person he knows. Ergo thanks Waver for all he taught in their little combat drills, and for some meditation techniques (mainly moon-viewing). Waver chose moon-viewing out of all mediation methods because it's Buddhist, and Ergo's Phantom Hands reminded him of those multi-armed bodhisattvas. Ergo's default five senses (and all other physical abilities) are better than Waver's reinforced five senses/physical abilities, so during his hair cut he could hear Waver talking about his plans to quit being a teacher. He asks if Waver doesn't like teaching, and he denies it. He didn't became a teacher because he wanted to, but he loved what he was doing. To explain why he's quitting, he decides to talk a little about his Grail War.
Back on Gray's side, Rin doesn't get to explain much because Gray already knew most of it, including the fact that Rin is friends with King Arthur. Rin moves on to her second question: why is Waver quitting. Gray answers that it's to focus full time on his research, and Rin is very displeased with this answer because there's no wrong choice here. Being a teacher is a good thing, and doing research is also a good thing. When asked about his research, Gray tells that she knows about King Arthur's summon because she hasn't age a day for the past 3 years, and Waver has been looking for a way to fix that at every second he's off the classrooms, but with their personalities, Waver would never tell her he's doing it for her, and she would would never tell him that she already knows.
Back on Ergo's side, the Grial War story was off-screened. Waver muses a bit about pratyaya, wondering if he was fated to get a student in a Grail War because he went to the Grail War with his teacher. This gets Ergo to wonder what did he do before to get so many nice people in his life now. Due to his amnesia, he could have been an evil murderer and not know it. He sounds a little afraid of learning about himself, but he still wants to stick around because he's been getting new fragments ever since he met Waver and Gray. Hearing that, Waver accepts him as a temporary student of the El-Melloi Classroom (or "event limited", if you're a nerd who uses gacha words like Waver does). Temporary because Ergo is not a mage, and because Waver is not planning on staying a teacher for long. The rest of the conversation is interrupted by giant wolves, spiders and birds made of bone coming out of the ocean and the beach sand. Once they're surrounded by the bone familiars, Tangere shows up and kindly asks Waver to hand Ergo to him. Waver muses on the irony of how Tangere could get things easily if he appeared two minutes ago, but now Ergo is officially a (temporary) student, so Waver will protect him. Waver activates his cigar Mystic Code, making a big smokescreen, but Tangere counters the lost visibility by simply exploding the bone familiars.
The book's color illustration is Ergo protecting Waver from all the flying shards. Once the smokescreen is cleared, Tangere tries to punch them directly, but Ergo blocks with 3 Phantom Hands, bending all of Tangere's fingers (which Tangere stops to manually unbend all of them).
Rin appears from the ocean, piloting her motorboat with one hand and machinegunning Gandrs at the bone birds with the other, because her Bounded Field alerted her of the intruder; while Gray approached from the other side and appeared from the mangrove.
Gray and Ergo team up against the bone familiars, and Gray is quick to notice they're not undead. Somewhere along their "it's so nice to fight by your side" banter, Ergo mentions that he's been feeling hungry more often since he started being around Gray. Ergo is practically handling the familiars on his because the Phantom Hands give him so much better range than what Gray has, so Gray goes straight to Tangere. She turns Add into the Battering Ram and slams it against Tangere's incoming fist, but Tangere just gets pushed back without taking major damage. It's like he predicted the size of the impact and adjusted his resistance to slide backwards on the sand without breaking. Rin follows up with her big jewel spell, but that fails to knock Tangere down. Rin is shocked because she managed to kill Heracles once with that, but on closer inspection they see that her spell punched a huge hole straight through Tangere's skull and only didn't knock him because there was nothing inside. Tangere takes advantage of this moment of shock to capture all three students with a bone whip. No one can escape the bone whip by force, so Gray turns on Arthuria's Dragon Core to melt the bones around her and readies Rhongomyniad. Before she can shoot, Latio tells her to stop. In Latio's physical discription, Gray estimates her age as 25, and comments that she's so pretty that it looks artificial. Gray complies to her request because Latio has a bone sword to Waver's throat.
We get this same scene again from Ergo's perspective. As he struggles to get out of the bone whip, he reminiscences on how he's only known Gray and Waver for a couple that, and even Rin, the person he's known for the longest, is someone he knows for less than a month, but due to his amnesia, their time together is a very sizable percentage of his memories, so he cares about them a lot. And then, Gray activates Arthuria's Dragon Core and Ergo suddenly shifts into a hyper-excited state, with his blood boiling and his mind fixated on how much he wants to devour her.
Back to Gray and Latio's stalemate, Gray shut downs Rhongomyniad after Waver and Latio agree on negotiating. Latio introduces her two units and exposits about the Atlas Institute's accelerated thoughts and thought partitioning, explaining how Tangere seemed like he was predicting their moves. She makes Tangere's bone whip let go of Rin, but Ergo is still tied. Rin demands Latio to release Ergo but argues that he absolutely can't be let out yet. The Phantom Hands stretch towards them against Ergo's command, but Tangere captures them with another bone whip. He complains about capturing the Phantom Hands being difficult because one of them can analise and deprogram his formula, but it shouldn't be a problem because he made this bone whip 3 times thicker. Waver questions the legality of Tangere because Atlas people aren't allowed to bring their weapons outside of their underground pit, but Latio explains he's allowed because he and the familiars are just Latio's bones. The Crudelis family uses their bones to create their Exoforms the exact same way the Eltnum family uses their nerves to create their Etherlites. The title of The Six Sources of Atlas was given to the six families whose tradition is about exploring the potential of the body, and the fact that they all have Lord-like status is merely incidental. Tangere and the unit named Latio are technically the same person operating on two separate units through the Atlas Institute's thought partitioning, but due to her granting Tangere an individual consciousness, he unfortunately developed his annoying funny man personality. Tangere is jokingly heartbroken by this description, talking about how he always saw himself as her little brother. Gray relates to Latio's exasperation because Add is exactly like that but much worse. With her introduction out of the way, Waver asks why she wants Ergo, and she answer he's her inheritance. Ergo is a product of an experiment by 3 three mages from 3 families. Waver immediately deduces that the involvement of 3 different families is the reason why he has 3 pairs of Phantom Hands. Each pair of arms comes from a separate factor each of the three families provided. Latio is impressed he was able to deduce so much with barely any hints, but Waver justify it saying their ritual is very similar to his own research, although his research is the exact opposite: how to rip a factor off of a person. Latio questions if he knows what exactly are these factors inside Ergo, and he reveals his long string of reasoning, connecting Yomotsuhegui to the Last Supper to finally say that Ergo ate the flesh of 3 gods, each provided by one of the 3 families involved. With everything explained, Rin is still very much not okay with Latio taking away someone she knows. Ergo argues he's better off just letting himself get taken without anyone having to fight, but since he said "this is better" instead of "I want this", Waver passes the number 1 lesson of the El-Melloi classroom: never take the easy way out. Negotiations are over. Everyone already made clear how (un)willing they are to concede. They all get ready to resume combat, but then a hawk appears. Waver, Rin, and Gray are startled because Singapore shouldn't have hawks, and Latio, Tangere, and Ergo are even more startled because they recognize the hawk as a Wuzhiqi. The Wuzhiqi says "Found you. Haha, can you remember me or did you forget?" and obliterates the right half of Ergo's head.
The chapter ends on a report from a magazine a few days later saying a crater shaped like a human hand was found on a beach.