The oddly isolated and family-less/friendless young woman is a flower (Hana), the man a wolf (Okami), and their progeny are stormy rain (Ame) and snow (Yuki). The man is transient and penniless, tries to get his education for free, lives off the woman, never marries the woman regardless of her pregnancy, steals food from neighbouring farmers, runs around at night and is gone for days, and eventually run over by a working class vehicle driving on the wrong side of the road.
His kids are just as wild as he is, proving much to much for the woman until she is eventually kicked out of her apartment and forced to move somewhere where she can hopefully hide the foreign half of her kids from the neighbours until they are old enough to do it themselves, as she insists is the only way to survive.
Yuki soon finds herself isolated at school because she is not as pleasant minded as the other girls, and only finds a true friend when she meets a boy who says he's okay with her foreign half even when that foreign half rises to the surface and causes her to attack him: young love.
Ame drops school to learn the ropes from some homeless dude in the forest who helps him see the light of his destiny. At the ripe old age of eight he decides to embrace the foreigner in himself and let it run wild to determine his lot in life, which results in having to leave his family and home, and head back to the wild where he came from.
So one kid shipped off, the other vowed to secrecy, and the whole foreigner thing just disappears; that is until someone tries to renew their visa. But then again, maybe not.