Le'an is a college student from a single-parent family. She lacks a sense of security, but she always bravely protects those around her. It wasn't until she met the most important person in her life, No. 5, That she learned to start relying on the people she liked like a little girl. Le'an, No. 5, And their good friends, what challenges will this group of young people face? Can people who love each other stay together for a long time?