that boy cried for me

Brothers, kinship, friendship, and love are completely two worlds. Fate makes them intersect.What will happen if two pairs of brothers, four kinds of lives, brotherhood and love are mixed together?Meng Zhao and Meng Xiao, Guan Qi and Guan Liang are their stories. Who will have any kind of intersection with whom?After the intersection, what will happen?Who missed whose life?