Sanzensekai no Ko o Koroshi

Tomorrow night, Hasumi, the female head of her clan, is bound by the elders' decree to conceive a child with a stranger—a fate she once tried to escape, nearly dying in the attempt. Now, on the eve of that cursed yet promised night, she must spend her last day with Yashiro, her chaperone who once intervened to save her from death. How will she face this desperate hour?