ABO, the world view is imaginary and purely fictitious.
As an A, Qin Yun accidentally marked O Han Yu, who was seven years younger than him. Later, they lived together to remove the mark, and Han Yu slowly fell in love with Qin Yun. Qin Yun rejected this relationship because of the age and experience gap, but had an accident when he went on a mission.
Han Yu guarded Qin Yun for seven years until he finally woke up.
Motto: Love is destined