I've Become the Villainess, and the Heroine Has Her Eye on Me. What Should I Do?

Written when the author was still inexperienced

[Transmigrate into a Book + Fantasy + Female Mermaid Lead + Master-Servant Relationship + Charismatic Female Lead with a Harem of Women]

Jiang Yiwen heard that there would be a meteor shower in Z City that night, so she specially bought a telescope to watch it. She wanted to make a wish: to be rich, really rich.

It seemed the heavens had heard her wish and whisked her straight into the recently popular tragic novel, The Sunken Light. Just as Jiang Yiwen touched her head, bewildered, a mechanical voice answered her: "Host, as long as you can change the ending to a happy one, we can grant your wish and give you five billion yuan."

"Five billion?!"

Jiang Yiwen's eyes widened as she covered her mouth in disbelief.

A moment later, her spirits soared, and she declared with fiery determination, "All I have to do is change the novel's ending to a happy one? Leave it to me! I promise I won't let you down!" She confidently thumped her chest.

It's just a tragic novel. Piece of cake!!