I Regret Marrying the Billionaire's Bipolar Grandson in My Sister's Place

I am the illegitimate daughter of a fallen wealthy family.

I married the bipolar grandson of a billionaire in my sister’s place, and now she regrets it.

She wore my nightgown and threw herself coquettishly into Lucas’s arms.

As for me, my body sank into the cold ocean.

My soul floated in mid-air, watching her slowly take my place step by step.

She thought she could live the life of a wealthy socialite from now on.

Little did she know that she had already stepped into the threshold of hell.