Angel's dead?

What would happen if an angel died?
Isabella was born with special powers and was made fun off since she was little.
One day she comes home to find an angel there waiting for her.
She is trained for about a year with an angel whose name he never tells.
One day he just vanishes with out a single trace.
News come to her later that he was killed protecting her from a battle going on now. Isabella goes to join the battle to find her one love.
Join her as she goes into battle to find her one true love.