A revenge from a different world

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A boy name Lucas Errendal saw a girl in the first day of his high school. He saw her going to the rooftop but he didn't stop her. She suicided and Lucas think it's his fault for not stopping the girl. He kept blaming himself for not stopping the girl. The girl started haunting him every night in his dreams and tell him to take responsibility. He was so scared at first, but when he know that the girl was asking him for help, he decided to revenge together with the girl. he meets the girl everyday in the dreams and what do you think will happen next? What will happen when Lucas and the girl who died starts a cool adventure? That was the start of the revenge from a different world.