Koujou Yakei: Aruga Rie Rensakushuu

Ao and Takaomi are two childhood friends living near an industrial area. Keeping their feelings hidden from one another, they carry on with their high school everyday.

"It's our final summer in school. Let's go see the factory nightscapes—just the two of us." This is their promise, and a romance begins to bloom. However, a certain incident spells turmoil for their budding relationship, placing them at the mercy of an unstoppable fate...

(Source: Kodansha, translated)