First of all, they aren't related. Now to the plot: Female lead gets isekai'd into a novel and she tries to protect her sister. Instead of her sister, she gets kidnapped by ML (which she called father when she was reading the novel). She tries her best to survive and avoid any way ML could be killed.
Uptade: Firstly it was great, after first season it got boring so i dropped it.
Seduce the Villain's Father