Listener's Paradox

After passing out on an exam, Haruki Tachibana got a bizarre dream of living the life of someone who looks exactly like him. After waking up from his dream, his parents were brutally killed while his sister, Isla, has been kidnapped by an individual with otherwordly abilities. By that, the world is facing a great danger. To stop that, he set a goal for himself- to become stronger and get Isla back.