have a problem with kh

ok i went and did all the tournaments and then after i beat cloud and all that i didn't see the little clip of hades talking to him and then having cerberus come like it did in my last game is this just some kind of glitch or am i missing something here??? cause im trying to get everyting and beat everyone and not being able to beat cerberus the ice giant and sephiroth is gettin in my way of that.

have you beaten hollow bastion for the second time ? If you havent thats probably it!