夢みる恋の結びかた

There is a shrine which is said to bring romance called Ataragi Shrine. At the shrine stands a cherry tree, which always blooms in summer, inside the shrine. The local legend says if a boy and a girl tie a string on a branch of the tree together, they'll be happy forever. 

One day, when Tomoya visits the shrine with Taiki, his friend, they meet a girl, Sasaya, in a miko's uniform. She is actually his classmate. Days later, when he bumps into her in front of his house, Sasaya suddenly says to him, "I... love you...." Also, three different girls, Asuka, Emiri and Koeda, suddenly start approaching him at the same time. 

Is it just a coincidence? Or is it because of the cherry tree? Like this, Tomoya's life dramatically changes....