Saishû heiki kanojo

There was this novel by Kafka, where Gregor Samsa turns into a coackroach. It's never explained why, or how, it just is. The point of the book is to explore human relationships, not magic.

This series isn't about world building or sci-fi, it's about people. There's a war, and it's never explained fully, nor they explain the major plot point. It just is. If you're uncomfortable with ambiguity, then avoid this anime.

In fact, I will praise this series for removing that. It's a bold move that forces you to focus on the characters. This is a sad love story, about aimless kids looking for their place.

Do not watch this if you're not in the right mental place. There's nothing jarring or shocking, other than pure distilled sadness.