A major motif in the story is the Japanese art of kintsugi (or kintsukuroi )—repairing broken pottery with gold to make it more beautiful for having been broken. Henry views his relationship with Grace through this lens, hoping to help her "put the pieces back together".
The title reflects the idea that love is ultimately a series of chemical reactions in the brain—sometimes lasting a lifetime, and sometimes "going supernova" before fading away. Reviews - I nostri cuori chimici | The StoryGraph
The two are thrown together as co-editors of the school newspaper.