no. According to the query of Collapse 3 official website, we can know that the four major plots of the open world, Sakura Samsara, are before the main line time (the main characters are Keren and Yaeyao Sakura), Destiny Headquarters is in the main line (but there are not many key plots), and The Post-Collapse Book is after the main line time, and it also has an excellent air combat system. Therefore, opening the world is not the main story.