From Kodansha:
Film enthusiast Mao Tsuchiya and his lone wolf roommate Hisashi Otomo make three promises:
① That Mao will never tell anyone that Hisashi is gay and has a boyfriend,
② That Hisashi will never approach Mao “in that way,” and
③ That they’ll respect each other’s “private time.”

The second-years’ ground rules should ensure a peaceful life together in their dorm, but the reality is never as simple as it seems in the movies, and some things are not so easily promised

Official English: MangaPlanet, Kodansha

Note: Vol 2 (Tasogare Outfocus Overlap) is a compilation of extra chapters, including the doujinshi Koiiro Soft Focus and is Vol 0 in the English release. The side story Zanzou Slow Motion is Vol 2 of the English.