Modern youth travel to a parallel earth that is invaded by dimensional rifts and monsters. People in this world can awaken their abilities at the age of 16. Human survivors form an alliance and open an academy for ability users to train guardians.
When the protagonist traveled through time, his adoptive parents were seriously injured while protecting him and his sister. After witnessing him standing up to protect himself, his sister had an emotional outburst and awakened her emotional abilities in advance, and she became dependent on him.
The protagonist relies on his extraordinary intelligence and takes protecting his sister as the bottom line. He becomes stronger step by step in the academy and helps his friends resolve crises. On the way, he meets several confidantes. In the end, he joins hands with his sister and them to end the rift crisis and stay together for a lifetime.
