A troubled young woman from a dysfunctional family drags her father into a world of incest and revenge after the murder of her mother and brother.

Correction: the daughter is the protagonist. But who is the antagonist?

Correction: the daughter is the protagonist. But who is the antagonist?

Who is the protagonist? Who is the antagonist (that is, do they know who the killer is)?

Who is the protagonist? Who is the antagonist (that is, do they know who the killer is)?

I think the second one you just gave is a lot clearer.

Yes she has an incestuous relationship with her father.

Alternative,

'Following the tragic murder of a mother and son, a devastated father and daughter are thrown together in a violent orgy of incest and revenge.'