Love the coloring and it is a pity that the story's a bit short. Felt sorry for the Onee-chan since she was only a tool for her younger sister and was collateral damage in the guy's revenge.
As for the younger sister, framing and using innocent people for blackmail and money... Yeah, I feel no pity for her.
Though I am curious how that guy was able to coordinate all those molesters into a single train on the schedule that the two sisters arrived.