Nearsighted girl Jiang Yaoyao is sent down the mountain by her father to find her second older brother, but she mistakes Ten Thousand Swords Mountain for Ten Thousand Tribulations Mountain and barges straight into the demon realm. Right in the middle of the street, she mistakes the Demon Lord's Second Young Master for her own brother. Her cultivation is only at the third level of Qi Refining, yet strange things keep happening around her. A broken wooden token makes everyone in the Demon Palace change their expressions, and on a rainy night, she senses an assassin's murderous intent before the attacker even makes a move. The Demon Lord's Second Young Master grows suspicious of her origins and decides to play along, pretending to be her second older brother. Amid a series of hilarious misunderstandings, the two gradually draw closer to the mystery of her true identity.