Sometime later, while Sidney is listening to a self-help tape in the bath, Isaiah breaks down the locked door and rapes him before telling him to "put that in his book" afterwards. Meanwhile, in the bedroom, Joan hears the struggle through the walls but does nothing to stop it; instead, choosing to drown it out by raising the volume on the television.
The next day, Sidney removes a secret copy of "Cocoon Man" from underneath the floorboards and attempts to leave the house with it, leading to another confrontation with Isaiah who scolds him and says that he's just as guilty as he is before trying to persuade him into giving up the memoir. However, an emotionally distraught Sidney merely runs out of the house and into the street only to be struck and killed by an oncoming van.
After Sidney's funeral, a grief-stricken Joan finally decides to confront Isaiah, asking him about what happened 10 years ago during his prom night which caused his father to lock himself in the bathroom and cry for hours. Trying to dodge the question, Isaiah says that he doesn't remember but Joan asks if that's when "all this" started.
Isaiah tries to convince Joan that she's being delusional, but she merely laughs before asking how he could kill his own father, causing him to lash out physically and claim that he "loved him better than she ever did" which causes their argument to escalate into a full-on fight to the death.
During the struggle Joan scratches Isaiah's face which causes him to throw her across the room and attempt to strangle her, only for Joan to stab him with a nearby knife in self-defense. Enraged, he kicks her in the stomach before trying to force her headfirst into a lit fireplace. Luckily for her, a fire iron allows Joan to escape from Isaiah's clutches and kill him in a state of grief and rage.
Having lost her family, an utterly distraught Joan throws the last copy of Cocoon Man into the fire as the credits roll.