In 20XX, dimensional tunnels appeared all over the world. Some people could go to different worlds through these tunnels. The few people who could go to other worlds brought technology, culture, and medicine from other worlds. Human technology advanced almost by leaps and bounds, and also cured diseases that had no cure before. People felt that it was a gift, until that day.
No one would have thought that the end of the world would appear as a blessing in the first place.
Intent: Restart after the end of the world