Something happens in my hati, tengah-tengah 

William & Yumi are best friends. Sissi started to hang out with them until Yumi felt in love with William. Yumi told him that, but William already told his feelings to Sissi. Yumi left their live heartbroken. William and Sissi had a baby and Sissi died at the birth and left 8 letters for the it to open one on every birthday. The last letter told to bring William & Yumi together.