Kurage no Hone wa Ao

On a summer day, as the cicadas chirped loudly. Haruka Nanami, a second-year high school girl, receives a confession of love from Kudo Satoru, a boy from another high school. Haruka is confused, telling him, "I've never even talked to you before..." Kudo suggests that they start out as friends, and the two exchange contacts. At the same time, at a nearby railroad crossing in town, a series of accidents occur. They are madly in love. They want to be together, but they can't. A midsummer love/horror story that you will never forget.

(Source: Kodansha, translated)