Minerva did not do that just for show. When she pulled James Potter into her office, the door was slammed shot, and every single legal spell, charm, ward, and hex for locking, privacy, and temporary self-warding she knew was show off around her, some aimed at the door, others the ceiling, portraits, as well as every single nook and cranny of the room. Then she let go of her former student and exploded.
"JAMES FLEAMONT POTTER! I DIDN'T YELL AT YOU IN FRONT OF YOUR STUDENTS OUT OF RESPECT FOR YOUR REPUTATION, BUT THIS! ILLUSIONS OF FILCH'S CAT EXPLODING IS ONE THING, YOU GOT A MONTH OF DETENTIONS FOR THAT ONE, BUT THIS? THIS IS TOO BLOODY FAR! YOU WENT OVERBOARD WITH THIS PRANK. YOU TIED YOUR SOUL AND YOUR LIFE FORCE TO A MEGALOMANIAC DARK LORD WHO WOULD LIKE NOTHING MORE THAN TO KILL OFF EVERYONE AND ANYONE! I CAN UNDERSTAND SPLITTING FROM THE ORDER, BUT THIS IS ONE STEP TOO FAR. DON'T THINK I DON'T KNOW WHAT YOUR EDITED LITTLE MARK MEANS. YOU SEEM TO HAVE LOST ALL COMMON SENSE SO LET ME POUND IT INTO YOUR HEAD FOR YOU. WHY IN MERLIN'S BLOODY BEARD WOULD YOU EVER SERVE A MEGALOMANIAC DARK LORD WHO IS HELL-BENT ON CONQUERING THE WHOLE MERLIN-BE-DAMNED WIZARDING WORLD TO MOULD IN HIS OWN SELF-IMAGE?!" Minerva McGonagall shouted, her voice louder than the already infamous Molly Prewett-Weasley HowlersTM.
James was unshaken. Minerva may have been like a second mother to him and Sirius (he even had the place of honor of causing her first grey hair, beating Sirius), but her rants always seemed to get to everyone but him. He smirked the traditional Black Family CrazySmirk™, Sirius had made sure to teach all the marauders that one. And Lily, on her it looked truly fearsome like no natural-born Black had ever managed. "Minnie, since when have I ever been led astray?"
Her eye twitched, and her nostrils flared, a rare talent she got from her animagus form (A/N: nope, actually a real thing, not just for certain animals or fictional nonhuman characters. I'm one of the people who got that talent, and yes, I do flare my nostrils when I'm annoyed). "Well, surprise me. What are you p;anning except for somehow coming out of this like you usually do, with sheer dumb luck?" she sniped at him in the thick scottish brogue that came out whenever she was annoyed.
"Minnie, you don't know the most of it, but let me let you in on my little trump card, and how you can help…." he whispered into her ear, she started nodding somewhere around after she calmed down, the second sentence in. By the time he explained the most important (for her) part of his plan, she was nodding along, and on board by the end. For all James Potter's faults, lack of ingenuity and getting out of impossible situations without a scratch on him was not one of them, so Miverva trusted her ex-student enough to follow him on his plans.
*** [A/N: Yes, this is the moment when i finally realized I have a plot in mind and started activating it.]
Severus Snape guled, but completed the apparition. He had heard the Potters had taken down their fidelius charm, so he had taken the opportunity to finally tell Lily what he should have said years ago. There were many benefits to a great lack of gryffindorness, not being able to brave up to say something was not one of them, especially when the results would most likely get him cursed to the ends of the earth and back again several times over.
Severus Snape, apprentice potions master under Horace Sluughorn appeared with a crack in the calm, almost sleepy-seeming village of Godric's Hollow and walked up to the door of the right cottage and knocked. Cottage wouldn't be the right word exactly, it was a large cottage that could have had 5 or 6 bedrooms just from the outside, with the inside magical expanded, it was nearly half the size of potter Manor, which was being rebuilt due to it being partially burnt down in an attempt at James' life when he announced his engagement to Lily.
Severus was lucky, or unlucky, he didn't know yet, that James was at Hogwarts and Lily opened the door.
She gave him a glare more fiery than any she had ever given anyone. If Lily were a basilisk, her look would not only kill, it would wipe Severus off the face of the earth. But she wasn't, so it only made him wish she would hurry up and kill him already.
"What is it, Snape?" she ground out, resisting, just barely, the urge to snap the door in his face to snap his crooked nose. She had already broken it once after he called her a mudblood, she could do it again.
"Lily…"
"It's Potter to you. I didn't give you the right to call me by my first name. I'll ask only one more time. What do you want?"
"Li- Potter, I wanted to apologize, make up the friendship we had… Please?" Snape hated to say this, but it was necessary. It was his own fault, tbus he'd forgive him. She was beautiful, wonderful, pure, that was Lily Evans. His mouth had betrayed him, but to him, she would never be Lily Potter.
"Unless you are ready to grovel, you can leave. You're half a dozen years too late."
"Please?"
She turned her back, and walked back into the house. He took that as a sign to follow. She came into the first room, a comfortable homey living room decorated in less bold, softer versions of gryffindor colors. She was cradling a toddler who could only be her son, miniature version of James Potter that he was, except the softer shape of his face and green eyes that could only have come from Lily.
She turned her face from the warm, kind, and loving gaze she was giving her son that Severus wished she would bestow upon him. Instead, she turned a glare on him. She cast an altered version of muffliato on her son so he wouldn't hear anything, and turned her gaze to him. "Snape, what the bloody hell do you think you can do to gain my forgiveness? You gave a prophecy to the Dark Lord that painted a target on my son's back bigger than all of bloody Hogwarts, conveniently forgetting the other half of the prophecy that literally warned it was self-fulfilling! Oh, and the one who mentioned that by the ancient calendar that was used in the days of Melin my husband also fit under the description! What did you want to do, get my family murdered and then conveniently be there to offer comfort?"
He didn't meet her eyes, regretting teaching her legilimency so that she could undetectably skim the mind better than anyone else. He gave up on just talking to her, and just dropped down on his knees, ready to start begging for forgiveness in a way he had been too prideful to try at the beginning, in fifth year. "Lily, please? I'll do anything!" He threw his wand down several feet away, out of easy reach, in a universal (for magicals) symbol of awaiting judgement.
"Anything?" she asked, curiously, innocently, sounding like the Lily he had grown up and fallen in love with.
"Anything. For your forgiveness I will do anything, so I swear it, may my own magic enforce the vow." he swore, thinking that the old Lily he had known would have taken that is enough and forgiven him.
Except this wasn't the old Lily he had known and grown up with. A skirk spread across her face, the traditional Black Family CrazySmirk™, looking so fearsome on her face, no words could describe it. "Legliminens." She cast, looking in his eyes. Just as she expected, they landed in a mental construct of a spot underneath a tree by a lake where he had first told her of magic (from the movie). Baby Harry had not been taken along for the trip, but neither had Severus Snaope's wand. In real life, they both stilled, eyes connected, Harry floating to his crib.
"Snape, I think there's a few vital pieces of information you missed. First of all, I call in Severus Snape's vow and his life debt to my magically bonded husband James Fleamont Potter, Head of House Potter, Gryffindor, and Peverell, to enact Servus Mancipium over Severus Tobias Snape, disowned son of House Prince."
He gaped. The Servus Mancipium [Slave Slave in Latin, I know, i'm just like -] would, if accepted, bind him to obey her every word and will, with his own magic and life force enforcing it. But at this point, he was unable to decline. "I accept the debt owed." He just hoped she would stop there.
"Good. Give me your left arm." He did so. She rolled up his sleeve, and muttered some words in an ancient language, most likely some verbal runes. His Dark Mark faded, instead replaced by the image of the triskelion, Merlin's symbol, topped by a lily, with a five pointed star inside a circle on the left, at one point of the triskelion, Mit being organa's symbol, on the right, at another point, the entwined crests of houses Gryffindor and Ravenclaw, and on the bottom, at the third point, a triangle, with a line and a circle inside, the symbol of House Peverell. Severus didn't know this, but Lily could wield it, as the Master of Death needed to unite not the three hallows, but the houses they symbolized, the power of House Emrys in the elder wand, Merlin's wand, which Antioch Peverell was the last to have the true allegiance of, House LeFay for the resurrection stone, which was in fact a rock much like the mirror of erised, created my Morgana and passed down to her godson Cadmus Peverell and then his line, the reason to it lost to time, and House Potter, creators of the invisibility cloak with Ignotius Peverell. With the three houses united into one with the fully magically binding marriage of James and Lily Potter, the powers of the Master and Mistress of Death were transferred to them as soon as they were ready to accept them, when they joined the Death Eaters and accepted there was no dark or light, good or evil in magic, only power and how it was purposed. Now, her symbol was on Severus' arm. To do so, she lifted up her own left sleeve, eliciting a gasp from Severus when he saw the tattoo on her own arm, last seen on Bellatrix's, the energy of which was repurposed to Severus' own.
"You're not the Lily I knew."
"Good, you're catching on. I have to thank you, you did me a favor, in my search to prove I wasn't a mudblood I stumbled upon a foolishly outlawed tradition. The blood ancestry test. Heiress of Merlin, Morgana, and quite possibly Rowena. Who knew?"
"You're not Lily. She would never do this!"
"No, I am very much Lily. You, on the other hand, now have your life and magic bound to my will. Fun, isn't it?"
They were both forced back into the physical world, kicked out of his mind because he fainted.
Just on time, James Potter apparated in. "Deer," he groaned at the joke, metally cursing Peter for making it up, "I conveniently have a piece of scum here bound to my will, and by extension yours, by his life and magic. Convenient, isn't it?"
James grinned. Things were coming along just fine.