Renketsu Houshiki

A cancer diagnosis upends Keisuke's life, suddenly forcing him to carry the weight of keeping the family liquor business alive. The plan: take over the business, marry the daughter of his father's old colleague, and hold everything together. Straightforward enough, except his sister Misaki refuses to accept it — and the reason goes well beyond typical sibling rivalry. The two of them share something they shouldn't, and when the fiancée's family is on their way over, Misaki makes that very clear. This 3-episode OVA from 2008 leans hard into the tension between family obligation and deeply personal, complicated feelings. It's not trying to be subtle about the taboo element — that's the whole point — but there's actual emotional weight behind it. The setup has real stakes: a dying father, an arranged marriage, a family legacy, and two people who can't untangle what they mean to each other. The drama feels grounded rather than gratuitous, which is what separates it from pure shock value. If you've watched Yosuga no Sora or Koi Kaze and found yourself genuinely invested in the emotional mess those stories created, this covers similar territory. It's adapted from manga, and the source material gives it enough structure to feel like a story rather than just a series of scenes. Don't go in expecting lighthearted romance — the tone is heavy, the situation is uncomfortable, and it's clearly designed that way.