In the school setting, the cannon-fodder gong was the first love and unattainable ideal of the protagonist shou in his youth. His own weakness cost him that relationship.
When the protagonist shou tries to win him back, he discovers that the cannon-fodder gong has long since gotten together with the class valedictorian from back then.
[Reader's Guide]
[The blurb covers the first two arcs. Each arc features one couple.]
[Please don’t read if you’re an extremely gong- or shou-focused fan.]