It drops you in the water before you know a single name: Summer B wakes up mid-shipwreck, spits out seawater, and immediately starts dying of things anime usually treats as scenery. No power-ups, no friendship speech, just Natsu crying because she is genuinely useless and knows it, Semimaru mouthing off to cover the panic, Arashi burning every calorie he has on the chance Hana is still alive somewhere on this ruined coast. Botan hands out the truth in doses because the full picture would break them. Then the show cuts to Summer A, kids raised in a shelter to be assets instead of people, and you understand why the survival test broke something in Ango that never healed. Yes, 170-plus chapters of Yumi Tamura got shoved into twelve episodes and it shows. It still lands the part where competence is the only mercy anyone gets.

Humanity saw the meteor coming. Rather than surrender to extinction, world governments enacted the Seven Seeds project: young, healthy people were frozen so they could outlive the impact and carry on the species. Japan chose five teams, named Spring, Summer A, Summer B, Autumn and Winter, each made up of seven members and a guide. The guides wear small vials of poison at their necks, a way out if things become unbearable. Once a computer decides the planet is fit for people again, the sleepers are revived into a cruel, perilous world, grieving loved ones they will never see again. Shy high schooler Natsu Iwashimizu wakes on a sinking boat in a storm beside strangers who all seem to have useful talents, while she can barely raise her voice. She has to keep up with them as they head for the Seven Fuji, refuges stocked with seeds and survival books.