Invisible String.

"She built a fortress around her shattered heart, each stone laid with ache of love lost. But someone knew her before the walls were raised, he knew her far beyond than anyone else. Even though, she always kept him at arm's length, he danced with her on the edge of friendship. Will the walls around her heart crumble? Or will he lose, the love of his life and his best friend?"

Tropes: Best friends to lovers, college romance, fluff, highschool.