Plansect Village (プランセクト村 Puransekuto Mura) is a monster village located in the Noah region that once boasted of having two separate types of monsters (insect and plant-based monsters) living in harmony with each other. The name of Plansect Village itself alludes to such a harmony: "Plan-" from Plant and "-sect" from Insect.
Luka initially wants to go there to witness this peaceful scene for himself after first hearing from a Tarantula Girl in Grand Noah Castle who claimed to be from there. Alice advises him to avoid it, however this only serves to fuel his curiosity.
When he arrives, he discovers the exact opposite of what he had expected - rather than living harmoniously together, the two separate factions of monsters were at war. Spotting Alra Arum and Alra Rooty losing a battle with a Mosquito Girl, Moth Girl, and Caterpillar Girl, Luka immediately sides with the plants. He defeats the insects, sealing all except the Caterpillar Girl who flees. The two plants thank him and agree to take him to their base of operations.
Luka then meets Alra Priestess, who convinces him to join their side. Their next plan would be to undergo what would appear to be a mass confrontation between the two factions, a distraction while they send Luka to assassinate Queen Bee, leader of the insects.
When Luka proceeds with the plan, Alice shows up and comments how "easily seduced" he was to join the plants. Luka questions her authority with her "cute subordinates" fighting over a pointless war; Alice responds that if she were to intervene and force a treaty, the two factions would immediately be at loggerheads once she left. She then states that a sacrifice is needed for coexistence.
En route to the insect hive, Luka is attacked by a Centipede Girl, a Silkworm Girl, and a Hornet Girl before finally meeting Queen Bee. She refuses to stand down, for she is defending her tribe. After a long battle, Luka seals her, thus ending the war...
...Or so it would seem. Alra Arum and Alra Rooty arrive and "celebrate" their victory by devouring the insects, much to Luka's horror. The two absorb a Hornet Girl, and, when Luka intervenes as they target a Caterpillar Girl, they declare him a traitor to their cause and proceed to attack him. He seals them both, turns to the Caterpillar Girl and asks if she would do the same, who replies how disgusting it would be to eat the plants that ate her friends.
A Mosquito Girl appears, reporting a massive army of plants not far from the hive. Luka rushes out and intercepts them, sealing the Alra Vore, Alra Parasol, Alra Prison, and any remaining followers. Amidst a finally peaceful glade of sealed plants, Alice arrives and tells him that his mistake was only listening to one side of the story. She tells him to follow his own convictions, not those of an image of a hero which he had used to vindicate his own actions. Frustrated, Luka decides to end this once and for all.
Luka fights Alra Priestess, who reveals that she'd had no intention of ending the war once the Queen Bee fell. After defeating the leader of the plants, he challenges their champions: the Canaan Sisters - Dorothy, Raffia and Deana. With the end of both the insect and plant leaders, the war is finally over.
The pacifists from both side then reveal themselves, coming out of hiding and helping to build peace within Plansect Village by first unsealing the monsters (except those who refused the peace, such as the Canaan Sisters).