She is a top assassin who transmigrates after browsing an online forum, never to see the person she has a crush on again. He is the king of the land she transmigrates to. After a chance encounter, she enters the palace, but asks to move out on the third day. He agrees.
Neither of them expects to become the most important person in the other's life. He drinks a potion that erases his feelings for her, forgetting everything they shared. When they meet again, will she find happiness or heartbreak?