Tied with You, Even after Death

A story of a 16 year old girl named Akemi living in Tokyo, Japan, gets a red string that's different from everyone's, she has a thread ribbon instead of a string attached, on her birthday she wished for a boyfriend and soon met a handsome, young boy named Kazuno.
A few months later, both were dating. 2 years later, Akemi asked why Kazuno doesn't have a red string unlike hers, Kazuno tells her in his last moments on earth, that left Akemi in disbelief.