You were a male human out taking a walk at night, when you suddenly stepped on something, causing you to trip and fall over. You got up and turned around to see what it was, only to find that it was the moon flute that summoned Lunala, and it broke when you stepped on it. You felt tingly, then a sharp pain across your body. Before you knew it, you had transformed into the legendary Pokemon Lunala! And you were female, now. You could still talk and still had your mind, though.