My Sister Picked Up The Male Lead

I couldn’t believe what happened before my eyes. “Sister, what is ‘this’?” “It’s your new friend, you said you needed a new friend no?” One day my sister picked up a man. It’s astounding to just “pick up a man”, but the more shocking fact is that this man… In a palace battle, he lost his memory. By day he was a child but by night he was an adult man. “I wish I was always in pain” “Huh? Why?” “Because Amy is always by my side” Why is this guy dangerous? In the morning, he’s a cute and lovable puppy…