He wish he could go back. Read every word between those lines before taking actions. Reverse everything from the beginning. The war is inevitable now. But only if he could make it back in the old days, he can be with her.
Make everything happen before it's too late again. Reverse the time as the leaves floats above again from its fall in autumn and make everything bloom in green when in summer.
Let him turn the switch of the clock. Let him finish it the other way around. This is a change of their fairytale. It's magical and ravishing in style.
And if he goes back now, let him love you once again.