This story caught me up and wouldn't let me go until I reached the end. I adored Severus and his cat. And the way that Harry and Severus interacted.
My only complaint, and it's minor in comparison to how much I loved about the story, is how easily Harry forgave Dumbledore (and even Severus) for turning his life upside-downin the name of the war against Voldemort. I understand why you did it that way, but I have to believe that some day Harry will erupt again over it all.
But really, as I said, it's a minor complaint for a story that I enjoyed reading.