Matsumoto's apocalyptic world is a brutal one (as most are). Rape, murder, and mutilation is abound here.
If you are not comfortable with that you should not start reading.
If you can continue you're diving into a stark and semi-nihilistic work showcasing the effects of trauma of children, the breakdown of society on humanity, and the pains of growth.
The main character is a violent boy named Shuu that acts as a neurotic and unstable lone-wolf sniper baiting out raider bands and killing them from a distance.
The secondary cast is mainly carried by Eliza, a girl about Shuu's age with possibly an even harsher violent streak and a deep desire for affection. And Makilda, an woman in her 20s that acts, or tries to act, as a mother figure to the children that end up orphaned in the commune she runs.
From that starting point we end up with a conflict between well-intentioned but possibly not brilliantly led order against destructive but horrifically competent chaos.
Its not a pleasant read by any stretch of the word. Neither does it give an easy catharsis for the struggle. But its still very much worth the read.
Matsumoto's art is wonderful through this, as rough and dirty as the apocalypse itself but gorgeous all the same.
The humor that is present is as black as it is genuinely funny.
A hard and unyielding manga, its very much worth the trouble to get through.