This botanical metaphor serves as the perfect framing device for the OVA’s narrative arc. The protagonist, the "sunflower," is ostensibly defined by her purity and her singular devotion to her partner (her "sun"). However, the "night" represents the hidden, shadowy side of her life—a space where the rules of the day do not apply.
She reached out, her fingers hovering over the petals. "You know why it’s exclusive, Kenji? Because it only blooms for those who are lonely enough to look for it. It turns its face away from the sun because the sun reveals too much. In the dark, we can be who we truly are." himawari+wa+yoru+ni+saku+ova+sunflower+ha+yoru+exclusive