Summary by Wrathkal
Story starts with a Marisa fighting against a tough enemy, suffering a small wound, but managing to kill it. Her children lick the wound, and Marisa admits that mister praying mantis was a tough opponent. Everything was a part of teaching her children how to hunt, while her pregnant mate Reimu stayed back in the nest, and they praise her strength. Emboldened by that, she viciously crushes an ant for daring to appear in front of the strong Marisa.
When they return, a human girl is waiting for them, and she's holding Reimu by the side braid. Marisa tells the girl to let Reimu go, or the strongest Marisa will punish her. Amused by that, she challenges Marisa to a duel, which make all the yukkuri taunt her and tell the girl to give up. Instead, she punches Reimu, and tells Marisa she'll kill them one by one starting with Reimu; if they don't want to die, they have to stop her. So saying, she begins hitting Reimu over and over.
Marisa keeps ramming against the girl's leg ineffectively, but is unable to do a thing as Reimu's unborn child oozes out of the mamumamu. Next, the girl twirls Reimu around by the hair, and knocks Marisa down repeatedly everytime Marisa gets up to save Reimu. The koyukkuris are unable to comprehend why their father can't do a thing despite being so strong.
As the girl tires, she suddenly loses her grip on Reimu, who flies into the air, only to get impaled on a branch and die. The girl expresses a bit of disappointment, but picks up the koyukkuris next and taunt Marisa to come save them. However, Marisa has realized that she cannot win, and bowing, begs the girl to spare the children, apologizing to them for being such a weak father. The koyukkuris understand that Marisa is throwing away her pride to save them, and do their best to comfort Marisa.
However, the girl crushes the Komarisa, then stomps on it when Marisa tries to lick it. She then proceeds to grind Koreimu's face into the bark of a tree, despite Marisa's attempts to stop her. She asks Marisa if Marisa is actually really weak, since she's losing to such a weak girl, and Marisa angrily retorts that a human girl like her is a weakling, making the girl stop.
Marisa's words reveal that she still believes herself to be the strongest, and the girl points out that she herself is actually quite weak, and that Marisa's beating of a praying mantis meant that the bug was weak, and calls Marisa the 'weakest', which injures Marisa mentally.
Earlier when she admitted that the girl was stronger, Marisa didn't think that she was weak, but hearing those words makes her recall the wound she received from the praying mantis, and Marisa starts hallucinating that the praying mantis in her hat isn't actually dead, but coming after her again. It isn't until she hears her child crying for help that Marisa snaps back to reality, but despite her pleas, the girl just reminds her that if she wants her child to live, she has to defeat the girl.
The girl later comments that this is the first time she's ever heard a yukkuri crying and begging her to 'please die'. But when Marisa tries to lick the child later, she finds that it no longer has its face. She then begs the girl to kill her. Laughing, the girl steps on Marisa, but slips on the bean paste that leaks out and falls.
She recognizes that as Marisa defeating her, but since Marisa has already defeated her, she can't kill Marisa despite Marisa's pleas for her to do so, so she leaves Marisa. Unable to move, Marisa ends up becoming food for the ants, suffering over a long period of time as they devour her, recognizing the fact that she's the weakest.
Two guys come hiking through the woods and find the corpse, realizing it had been stepped on due to the shoeprint left in it. Also, Marisa's face isn't just filled with pain, but despair as well, and they figure out the gist of what happened from that and the size of the shoe. The story ends with them expressing amazement that a young girl could have done something like this, and their determination not to lose to her.