I Transmigrated to Ancient Times and Became the Strongest Crown Prince

I have to admit that Imperial Physician Huang really is a miracle worker. Though I've possessed the Crown Prince's body, I can feel my health gradually improving. I've got energy to spare all over, and I really want to go box, but I just can't open my eyes. I don't know what's going on. Sigh, was I happy for nothing? Did I end up in a vegetative state? Damn it, give me something to work with! That night, somewhere between dreaming and waking, I saw an old man with a white beard slowly emerge from a cloud of white mist. Stroking his beard, he said, "You were not meant to be here. But since you have come, make the best of it. Civil war is about to erupt in the Great Qi Kingdom, and you have a heavy responsibility to bear." With that, he vanished. "Hey, old man, at least explain what you mean..."