The Swallows Will Not Return is based on the novel of the same name by Natsuo Kirino. It's about a young woman named Riki who lives in desperate poverty. She becomes a surrogate mother out of desperation and is bought by a wealthy infertile couple who want her because she resembles the wife. The manga discusses and depicts explicit sexual topics and is highly concerned with women's (and to a lesser extent, men's) bodily autonomy.