Luna is a loveable, mischievous, and lively young girl. She bathes everyone around her in her aura of cheerfulness, starting with her two best friends: Nell Grace, a lonely young woman, concentrated on her studies and slightly out of step with her peers, and Sully Cartwright, a young man who can only hide his sadness behind a smile. Despite sharing Luna as their best friend, Sully and Nell loathe each other.
However, all that will change for the group of friends when Luna dies of cancer. Before dying, the young woman has arranged for her best friends, Nell and Sully, to meet once a month to stop them from mourning alone. And, despite their strong reluctance, they gradually find common interests and come to appreciate each other being there.
Has Luna succeeded in understanding the bonds that tie her best friends together to create a beautiful love story?