"Planetarian" by Suzumoto Yuuichi. A follow up to the game of the same name, this book consists of ~25% extra laughs and ~75% more depression.
The original Planetarian game was set in a post-apocalyptic world, where a scavenger meets Yumemi, a robotic guide for a planetarium. It's a heartwarming story of how a human finds a moment of joy in life thanks to a clumsy robot, in an otherwise mostly hopeless world. This book adds a bit more to the before and after timelines of this world.
Yumemi appears in the first chapter, a prequel where readers learn that she has been slightly broken even before all the war and destruction took place. But the root cause to her malfunctioning is actually buried deep in the memory stack, which was addressed in a very personal way. We might have all seen similar things that don't quite work in mysterious ways, but we are so attached to those things that we are afraid of "fixing" them, for the fear that it would remove their character. This chapter presents that situation in a quirky way, and it's the most fun chapter in this book.
The remaining three chapters go from slightly depressing to moderately depressing to "we are all doomed" level of depression. Starting with a war episode of the past, followed by the final presentation of a traveling astronomer (former scavenger), and ends with a distant world where only the memories are preserved. It felt quite grim the first time I read it, but if you are a hardcore optimist, you might look for the common feature shared by all three endings, which is that a bit of hope lives on even when it's freezing hell all over. Well, it still felt quite grim the second time I read it.
This is the second time I read this book, having dug out the book from my bookshelf after hearing news that Planetarian will be animated. The original Planetarian game was published by Key over a decade ago. Key is best known for their heartwarming stories that first make you laugh and then make you cry, Planetarian followed the same structure, but also had the extra feature that it was short, so your game induced depression ends in about a weekend or so. It was so short that I bought this book to get a bit more Planetarian, totally not expecting that it would be animated in 2016. For years I have waited! There is hope in this world after all.
Previous (2016-06-04): "Bungaku Shoujo" series by Nomura Mizuki
Next (2016-06-16): "Kono Subarashii Sekai ni Shukufuku wo!" volume 4 by Akatsuki Natsume