As October turned to November Harry grew more bored in his classes and leaned more and more on his independent studies to keep himself happy. Socially he found himself connecting to older students more than his peers as older students investigated the school wide study group. He didn't leave his peers behind but he helped older students begin to build the same connections between each other that the first years had been building.
Most of the teachers were puzzled because the tensions that had existed for as long as they could remember between students of different houses were gradually fading. McGonagall, Flitwick and Sprout thought it was the most wonderful thing. Snape was too busy trying not to break his oath to pay attention to what was happening to the school as a whole. It was a week before November began when Severus Snape finally cracked and asked the Deputy Headmistress and the Headmaster to meet with him.
"Yes, Severus, what is it you need?" Minerva was concerned for her colleague. It hadn't escaped her that as term went on he had grown more distressed and his changes couldn't help but be noticed.
"I'm afraid I must give notice. I will finish out the year, but teaching has never been my first choice of career. You will have to find another Potion Master next year."
"Severus, how can you possibly consider leaving me in the lurch like this?" Albus said. "What if-?"
"Albus, this was always your plan, your way! Not once in all your planning did you ever consider the thoughts, feelings, or needs of your pawns in this chess match you have with the Dark Lord. I may believe the Dark Lord is still out there, I have promised to help bring him down, but I no longer trust that the path you want our world to tread is the correct one. I think you've lost it, old man. You have forced me here, under your thumb, to do your bidding all these years since I took the prophecy to Voldemort, unknowingly betraying my best friend. But I CANNOT do this anymore. I beg you let go before you destroy me, this school, and our world. I feel like I'm on the verge of being destroyed, I can't do this anymore. Please, let me go. Please, Albus. Be the good person I've always believed you to be not the ethically bankrupt person the press has painted you the last few years."
"And if he comes back, Severus?"
"If he comes back we can revisit this issue."
Minerva felt somewhat confused by the conversation between the two men. But she was also aware that Sirius and his allies were working to remove Dumbledore from the school anyway.
"Thank you for giving us so much notice, Severus. I will of course consult you with regards to your replacement, both as Potion Master and Head of Slytherin House." She thanked the Potion Master.
The prank Harry planned for Dumbledore would be epic. The old man wouldn't be able to resist the multicolor robe based off the costume from the Joseph and His Technicolor Dream-coat musical. Harry laughed. The coat, like Sirius' band-aid the day he left London, wouldn't radiate magic because it would be dependent on Dumbledore's magic. The spells were all being done as quilting stitches done in thread the same colors as the fabric they were being stitched onto. The trick was going to be how to turn it off.
Since the coat would transform with him it had to have a separate turn off switch. Harry decided on a using a potion to turn it off, because it would be easier and less traceable for it to be delivered that way. He had thought Miss Parker would frown on his little project, but she liked the complexity of the spells required enough that she wasn't saying anything.
Dumbles had tried twice more to corner Harry, but Minerva played the Head of House card and interfered before the old man got to the point. Harry learned via Fred and George that the students found the cerberus that was guarding the third floor corridor. Which meant the stone had many protections beyond the ones he'd seen in Severus Snape's mind, probably one from each major field of magic and the students were undoubtedly in danger courtesy of the Headmaster.