Gokukoku no Brynhildr

A high school student named Ryōta Murakami is haunted by the memory of his childhood friend, who died in an accident he blames himself for. To honor their shared promise of proving aliens exist, he joins the astronomy club and gazes at the sky. When a transfer student named Neko Kuroha arrives, she closely resembles his lost friend. Neko reveals she is a magic-user who has escaped from a research laboratory.