The Anime Lad
Shion belongs to the privileged elite of No. 6, one of the city-states left after a great war. His protected future changes after he lets a mysterious boy called Rat stay in his apartment. The city strips away his privileges and sends him to the outskirts, turning one act of compassion into a new view of its promised perfection.
Super Eyepatch Fox
Live among the privileged in a city built to seem perfect. Give shelter to a strange boy called Rat. Lose that protected place when the authorities learn what happened. No.6 begins by making Shion pay for a compassionate choice, then leaves him outside the life he once understood.
Gigguku
Shion has every reason to protect his comfortable future, then a mysterious boy needs shelter and he helps. That single decision costs him everything the city promised. I love how directly the premise tests No. 6. If one compassionate act can turn a privileged child into an exile, perfection was always a very narrow offer.
Father's Basement
The sinister perfect city is well-worn science-fiction territory, and the setup announces its suspicion early. Shion gives it a sharper scale. He is not opposing a system in the abstract. He helps one stranger, and No. 6 withdraws his privileges. The punishment tells us enough without revealing what larger secrets the city may hold.