The Sweetheart Heroine's Plain Little Sister Awakens

[Period setting + transmigration into a book + sweet romance + power fantasy, 1v1]

After the original period novel's power-fantasy heroine gets married, the story comes to an end. Gu Rou, her once-frail younger sister, encounters Lu Chaoyang, the next male lead chosen by the System, who has transmigrated into the book. She awakens to her own consciousness.

Gu Rou: “What? He transmigrated here!”

Lu Chaoyang: “What? She's the heroine's younger sister!”

Later, just as Lu Chaoyang decides to stay in the book for Gu Rou, he discovers that Gu Rou's origins may not be so ordinary after all...