The main story, Hyakuoku Nengo no Kimi no Koe mo, is a shoujo romance about a girl and how she deals with the death of her boyfriend.
Instinct and a Chromosome is the extra one-shot at the end of the volume that was scanlated by Lililicious. It's an angsty but sweet tale of two women in love. Nanako is glad to escape the stifling atmosphere of her hometown and come to Tokyo…