S1.E1 ∙ Episode #1.12013The Little Sister's Promise YAY-. IT'S A PROMISE. ONII-CHAN 2 YEARS LATER ONII-CHAN, I'VE GROWN UP NOW. WHEN I GROW UP, I'LL BECOME ONII-CHAN'S WIFE. AND SO, MY SISTER OF GROW ING UP. Can't breathe ALL RIGHT, IT'S A PRO-MISE.Rate