15-years-old Itami Suzuki grew up in in a house filled with music. Due to this, his life has long been revolving around it and has became a part of his everyday life.

However, because of a traumatizing event resulting in the lost of his childhood friend, his world shutters.

He blames himself for her death forcing him to put away the guitar given by her; all the while abandoning and disengaging himself to music completely.

It has been 2 years since then, yet that memory is still engraved in his mind.

But in one fateful spring after moving to a different city and beginning his last year of high school; Itami, now 17, found something in his old jacket.

It was a letter left behind by Haruka, his childhood friend that once influenced his life so much.

Avoiding to read the letter and keeping it away not wanting to revisit the dark past, a strange girl claiming to be her suddenly appeared on that same day; just as he was halfway to school.

Although Itami doubts her at first, looking closer, she really does look like Haruka when she was still alive; having the same short dark-blue hair and in a uniform back when they were in junior high school.

But the reason for her sudden appearance might change the way he perceived himself and this weird encounter might offer him a chance to finally heal from his trauma, by returning to what connected him to Haruka for the last time...

Through a serenade.