The story of "the literature girl and the chemistry girl."
Looking-glass Insects is the third chapter of Subarashiki Hibi. Takashima Zakuro's perspective chapter. Looking-glass Insects takes us back to early July, before Zakuro's suicide for the first time, due to this, we finally get to see the events that led up to the trigger for the main story.
The tale of the battle of two girls. They use literature and chemistry to fight reality. Literature is a strong will, chemistry is a force of the physical world. These two are their only weapons against reality.
Looking-glass Insects has two endings, the Kimika End, and the Looking-glass Insects End. Jabberwocky I only unlocks upon completion of the Looking-glass Insects End.