It's a love and let go world we live in

Have you ever heard that if you love something then let it go? Well is that saying always true? What if the one you love goes and gets himself killed after you let him go? Is it your fault he died? Well Mizuki Haruzuka, a high school delinquent of sorts, learns the feeling of regret by letting the one he loved go. He fell in love with another guy so he wonders whether he's at fault for letting himself feel that way or if it really was just the will of the world for it to end up this way, to end up with him all alone.