D&D: You agree to perform the ritual
From Create Your Own Story
While in another time you might not even consider it, you are just too weak and abused to resist him anymore. You are afraid that if you refuse, he will continue to torture you until he will break you mentally anyway. And by agreeing to the ritual, you will be spared that. He is a powerful mage after all (although under different circumstances you think you could have defeated him...), and probably with you under his command he will become more powerful. Maybe he will even send you on quests, as your loyalty will be guaranteed...
"Okay, I agree to this ritual" you answer.
"I am glad you saw reason", he answers, "I will prepare the required spells and magical components and we will perform it tomorrow".
The next day you are brought to his laboratory again, where you see the preparations are complete. You are untied and instructed to stand between some magical glyphs he conjured on the floor.
He approaches you, and says "I will have to remove your collar, as its magic-blocking abilities might interfere with the ritual. I trust you will not try to do anything stupid... but in any case, remember this" and he points to the other side of the room, where about a dozen of his guards are stationed, some with loaded crossbows aimed at you.
He proceeds to remove your collar, and you suddenly feels your magical abilities flow back to you. He takes his place, near a large brazier, with all the components assembled next to it. "Stay still, as we don't want any mishap to happen during the ritual, and remember - you must not resist the magical energy that will flow into you, otherwise - who knows that the outcome will be!" he says.
What happens next:
D&D: You stand still and the ritual is performed smoothly