Momonga enjoying a steam bath on the 9th Floor in Spa Resort Nazarick enjoys the time relaxing while being attended by Miyoshi, his bathing attendant. Momonga hopes to use some of the other facilities on the area, though sadly many of them were damaged due to the Cracks. He wonders if they should rebuild it and gets an idea that he should have his subordinates prioritize its reconstruction. With the facilities back up and running it will hopefully relieve the Floor Guardians' fatigue after dealing with the Nazarick's rebuilding, rampant Chaos Beasts and other issues they been dealing with since coming to the New World.
Later in the Round Table Room, Momonga puts his proposal to his Floor Guardians. They are receptive on the idea to help cope with all their tension. Though Demiurge makes a note that if they repair the baths and enjoy themselves, they will be vulnerable to a Chaos Beast attack as they will bathe without their equipment. Seeing his point Momonga and Demiurge come up with a plan to have a cohort of undead stand guard around Spa Resort Nazarick while the Floor Guardians and master will keep their equipment in the vicinity just in case. Momonga uncomfortable of the idea of undead standing guard while he bathes makes a suggestion in using golems, as they are cheap and tireless and allow for customization.
Plans are made to install golems within the bath area for additional security and as inconspicuous as possible. However as Albedo and Demiurge go over the plans with Momonga, they find that it may be difficult as many of the golems within the Great Tomb of Nazarick were destroyed during the transfer to the New World. Surprisingly one particular golem managed to survive unscathed much to Momonga's annoyance due to its creator. Finding this unacceptable Albedo has authorized a band to search out materials or technologies in the New World that may help repair their constructs.
The search begins in E-Rantel where the protagonist meets Leinas Rockbruise and attempts to engage her in a conversation. Particularly in the topic of golems, in order to gauge the New World's level of sophistication, sadly she cannot reveal much as that matter is a state secret and not within her expertise. After the protagonist finishes his conversation with Leinas, he meets with his party member Slimeko. While their findings so far are disappointing they hear a commotion from a few fellow adventurers that a lizardman had attempted to enter the city seeking aid for his people due to the temperature of the his home rising, but was turned away by the city guards. While Slmeko doesn't think much of it, save for the protagonist, who thinks the cause of the temperature increase could indicate the possible existence of the World Item Caloric Stone, a substance that could be used to make weapons and golems.
Interested in the group decide to investigate, though by the time they reach the gates the guard tells them that demi-human was turned away but is located further down the road as he has not given up seeking. The lizardman has taken to sitting by the road, asking any adventurer his request but is treated with fear and hostility due to be a non-human. The two approach him and he notices them he asks them if they are adventurers and are interested in his story. The two confirm and introduce themselves. The lizardman grateful for having some open minded people, introduces himself as Zaryusu Shasha, a Traveler of Green Claw from the area between the Great Forest of Tob and the Azerlisia Mountains in the vicinity of the Great Lake. He briefly explains that his people live in their in peace, subsisting the fish in the waters. However, the water temperature of the lake suddenly began to rise for awhile. It was only a slight change, but grew warmer from the north side of the lake. Eventually, the temperature rose and began to affect the local fauna in the area resulting in some insects and fish no longer being able to survive in the water and the fish that depend on them for food are also dying of hunger. Sooner or later this will affect the lizardmen. Since the phenomena that caused the Crack are still unknown to the lizardmen, Zaryusu sought the aid of humans as they have more knowledge on it. Sadly his people refuse to accept help from humanity despite the dire consequences hence why he came alone. Zaryusu asks the two if they will help him for which the protagonist asks the demi-human to wait as he contacts Momonga.
Momonga ecstatic that Caloric Stone may be in the New World. Albedo is cautions for being too hopefully, though the Overlord states that in the past Ainz Ooal Gown had once collected one of the Prismatic Ores and under certain conditions was transformed in Caloric Stone and benefited from it many uses. Even if it's just a rumor Nazarick must lay a claim on this resource before another takes it. Momonga then orders the protagonist to investigate the claim immediately. The protagonist relays to Zaryusu that they will accept the lizardman's request. The demi-human though grateful is not confident that the protagonist and Slimeko will be able to hold themselves in a fight, but is assured that they will be bringing some help. They suggest tomorrow morning they regroup a bit away from the city's highway to avoid attention from the guards.
The next day, the trio wait for their support to come, when Zaryusu sixth sense detects someone approaching. It turns out to be the Floor Guardians Cocytus and Aura Bella Fiora. The two greet their colleagues from Nazarick and introduce them to the lizardmen. Zaryusu is initially confused by the elf and insect as he did not think humans were tolerant of other races, still believing Slimeko and the protagonist to humans. He is told by the protagonist that they represent a faction with a philosophy believe they must unite as the current situation in the world has prompted them to work together. Zaryusu agrees with such thoughts and sincerely welcome the two into the party.
While traveling to the the group are attacked by bandits but are repulsed by Zaryusu and Cocytus. Taking care of their enemies, Aura wonder why the bandits attacked them even though there was a difference in strength. The protagonist hypothesize that the bandits attacked them out of desperation due to the encroaching Cracks, Contaminated Beasts and Chaos Beasts. Zaryusu agrees that it's the same for all races and compliments on Aura's and Cocytus's skills. He asks if either of them could use Martial Arts, only for Cocytus to state they should hurry before more enemies come.
Later the group sit down and have lunch, Aura notices Zaryusu's meal to be a dried fish and asks if it's from his village. The traveler says it's a fish that he raised on his fish farm his own project that he developed on his own. Zaryusu goes onto explain prior to him becoming a traveler, there was a great war among the seven tribes of lizardmen due to the shortages of fish in the lake. As a result of the war two of the tribes were destroyed but proved to be a mixed blessing as their reduced numbers allowed them to overcome the food shortages. However Zaryusu sought to find a war to prevent history from repeating and became a traveler to seek new knowledge. When he returned home, he started his fish farm in hopes it will provide food for his tribe. Cocytus listening to Zaryusu's story admires his forward thinking and his people. The others comment on agreement. Zaryusu comments on the strangeness of working with various races and admires humanity working together whilst his kind still fight, though Slimeko states that maybe in the future that may change.
Before rushing to the wetlands, the group reach the edge of the Great Forest of Tob. The lizardman cautions in entering as he had to make several detours to avoid Contaminated Beasts and Chaotic Beasts. Still pressed for time, if they take too many detours night will fall, hence Aura calls her pet, Hamsuke who immediately arrives from the woods. Zaryusu initially shocked by the rumored Wise King of the Forest learns the beast will be acting as their guide through the forest. The group enter and encounter a Contaminated Beast which they defeat and finally reach the wetlands area around night time. The lizardman then leads them to a safe campsite used by the hunters of his tribe.
By morning the group heads to the village of Green Claw, where they are given a wary reception by the inhabitants. The chieftain, Shasuryu Shasha and older brother of Zaryusu welcomes his sibling safe return and his allies. Taking them to the side to avoid attention, the chieftain explains the situation so far. The temperature of the northern part of the lake is still rising and the cause is still unknown. Green Claw has not taken any action to investigate for various reasons, like the dangerous beasts that live in that area, but also to avoid incite aggression with the other tribes if they send a party from Green Claw there. So far only the tribes that Green Claw has friendly relations are aware of the situation but not all. Zaryusu claims that the situation would be better if all the tribes were working together, but his older brother claims it to be impossible as there is still too much blood spilled. However since Zaryusu is a traveler and his friends are outsiders they are investigate the lake without the other tribes inciting violence against Green Claw. Still Shasuryu apologizes to his brother for putting the tribe before him, but Zaryusu understands and leads the party to the north. Along the way the traveler explains to his friends how supportive his brother has been since he became a traveler even taking care of his pet Hydra Rororo, which Aura wishes to see. Zaryusu promises to show her to him when the crisis is over as they cannot bring his pet as it would attract too much attention. He warns of the possibility of encountering lizardmen from other tribes. Negotiations will be handled by him and if that fails they may need to fight, but shouldn't be a problem for them considering their collective strength.
While journeying through the wetlands, Zaryusu notices that the local creatures have changed and monsters are coming down from the mountains and wonders what happened. Its hypothesized by the protagonist that a Crack has opened up there, though Zaryusu is not sure as no Chaos Beasts have come down the mountains so far. Slimeko and Aura detect a band of lizardmen approaching. They reveal themselves to be hunters from Dragon Tusk sent by their chieftain to investigate the area. They recognize the Zaryusu as the holder of Frost Pain and ask what is Green Claw doing in the area. The traveler corrects them stating he is an independent doing an investigation of the northern region. Seeing his companions especially Cocytus they demand why the traveler is working with a monster. Zaryusu defends Cocytus stating he is a honorable warrior and friend assisting him on his mission. The lizardmen unconvinced bring out their weapons for a fight. The lizardmen are easily bested by the Floor Guardian. The group seeing the difference in power ask why is such a powerful creature helping Zaryusu who tells they that he and his friends are a group of beings that are forging bonds beyond race and the they should follow in example if they wish to survive. The lizardmen don't understand his words but decide to leave and pass on his message to their chieftain.
Reaching the lakeside at the north the group confirm that the water to be warmer that expected. Postulating that something in the water may be the cause Zaryusu volunteers to swim beneath the waters and investigate. Going under the party wait for his return. The traveler suddenly resurfaces calling out in warning as he dashing back to shore. The group are a bit confused until several Giant Lizards erupt from the water.
Trying another approach for the operation, Cocytus creates two small footholds in the water using [Ice Pillar] for him and Zaryusu to use while fighting the Contaminated Beasts in the water, while Aura on the shore provides support using her bow. The duo they begin their assault the the creates from the safety of the ice pillars until a larger specimen emerges form the lake. The creature heads towards the pillars causing the two warriors to activate [Frost Aura] and [Icy Burst]. Despite it being covered in ice, the creature continues to press on the attack. The warriors retaliate with slashes from their weapons causing the beast to roar. It lashes out and hits Cocytus. Cocytus restrains it and has Zaryusu hit it with another [Icy Burst] into its mouth. Cocytus manages to land a killing blow with his [Kulika Blade].
Having successfully killed the beasts, the group drag the bodies out of the water and learn that the heat coming from the bodies is causing the water to increase. The protagonist does a more in-depth examination and after having Cocytus slice the belly of one of the monster, discovers a strange stone that emits heat. Seeing the stone to be the cause of the Contaminated Beasts increased heat, the protagonist theorizes that these beast most have consumed them after being affected by a Crack to digest their food. The creatures and the stones may have come from the Azerlisia Mountains and sought the Great Lake as a breeding ground. The protagonist decides to take a sample to bring back to Nazarick for study.
Back at Nazarick, Momonga confirms that the project for restoring Spa Resort Nazarick has been successful. All thanks to the heatstones discovered in the Great Lake. While not the expected Caloric Stone, it still has uses such as repairing golems and complementing the bath heating systems. In addition it is a prime example that the New World possesses minerals unknown to YGGDRASIL. They have acquired a stable source via the route to the Great Lake, and the chieftain of Green Claw grateful for Nazarick's assistance is even offering to trade the ores to them. Now that they are developing good relations with the lizardmen and the baths and repaired, Momonga decides to spend a day in the baths with his Floor Guardians. The men lead by Momonga enjoy their time in the men's section while the women have their section. However the men are disturbed when they hear a commotion on the other side. Shalltear Bloodfallen after speaking lewdly about peeping on the men's section to see Momonga's naked body, inadvertedly activates the Lion Golem, a golem that escaped being destroyed during Nazarick's transfer. It attacks the women which is heard by the Momonga and the men. Getting up Momonga and the others decides to assist Albedo and her colleagues.