Could also use some translator love.
If I'm not wrong the story goes like:
Mister brought his pet Koreimu to the park to play in the sand pit, while Koreimu is playing in the sand pit, mister said to her that he'll go to the convenience store and left her there.
The park has some yukkuris act as law keeping squad to keep strays away from the park, Marisa being a member of the law keeping squad determines that Koreimu is a stray because she doesn't have a badge and punished her, after Koreimu dies, mister appeared and said that was interesting and he's going to upload the video, Marisa then goes back to the squad.
Back at her squad, Marisa gives her report to Alice and reveals that she know all along that Koreimu was a pet and that mister is an abuser, unable to live with the fact that she kill an innocent yukkuri, she resigns and goes back to stray to take revenge on mister for Koreimu.
After searching for sometime, Marisa found mister, now with a Baby Flandre, Marisa tried to tell Baby flandre that mister is a bad human that kills yukkuri but it didn't believe her, Marisa is killed by mister while trying to avenge Koreimu and found himself in the afterlife where she find Koreimu playing in a sand pit.
Apologizing to Koreimu, Marisa found that she didn't hold a grudge and is waiting for mister to come, she then ask Marisa to play with her while waiting for mister, while making mud dumpling in the sand pit, Baby Flandre soon comes and apologizes to Marisa who figured that she's also killed by mister, the three yukkuris then play in the sand pit together until a yukkuri Sakuya appeared.
just gonna add a bit: the community work yukkuri open a service called "pet yukkuri collection". owners who no longer want to raise their pets would either throw the yukkuri away or kill it, but due to the pets being badged and tracked by chips, they cannot be thrown away; and killing them by their own hands would cause hatred towards the humans. so the owners in turn hire the community work yukkuri to do the dirty work. the killed pet yukkuri would then be sent to the factory, thus "pet yukkuri collection".
killing off shithead pets is one thing, but cases in which anons simply hiring the community workers to kill pets for their own entertainment, while the victim themselves are innocent, loving niceheads have increased, and this particular job with the koreimu was Marisa's breaking point.
this is a particularly unique and high quality work that shows a deeper sentimental side to the average yukkuri, and condemns the unreasonable abusers (the kinds in kiriraitaa's works, except for the house yu comic). and personally, I swear I'll snap anon's neck for killing the Flan. nobody touches predators on my watch.
also, the Flan was a tarinai, as you can see how she says "pi" and "pya" all the time, with only a single line of intelligible but broken speech. this would make it the first time where I see a tarinai as cute and lovable.