[Spoilers] Why do the girls come to the conclusion...

[Loops]

that the death of Zoe's sister isn't Zoe's fault? I understand guilt is eating her up but who's fault is it if not hers? She invited her there! And also didn't have the strength to save her, although that's a not exactly the cause of death, but still...

[Nibbie]

She still agreed to come, and was the one who presumably slipped up and fell into the river. Also, they were children, neither of them fully understood the potential consequences of their actions.

[Loops]

Just because they were both still young and dumb doesn't absolve both twins from responsibility, including Zoe. The parents are also rightfully to blame, and it seems like for a while everyone understood their share of responsibility, because Zoe mentioned that the house went hollow after the accident. But why pretend that it wasn't her fault, partially? Basically the moral of the story if to lie to yourself to cope with your ♥♥♥♥ up. This may even be valid advice, but it's kinda brushed over so quickly...