They are unbreakable. The friendship they built was strong enough to surpass everything that will try to tear them apart or so they thought. Sharon and Alex shared the same dream; lived on the same roof until one unexpected event rips the bond between them, Sharon needs to fly to Japan because of her grandfather's will and left no choice but to move to Japan right away. They promised to dance again together but when Sharon came back to Korea, she saw Alex in a wheelchair; unable to walk. She witnessed the lost rhythm inside her childhood friend's heart.