Okay, so it turns out it is her sister. Here's what I translated so far:
Pimcahnok a hot n'rai recieves her will from after her mother's death.She enters the entertainment business with her manager Charlie. Charlie wanted to raise her as a best n'ek, but somehow she's more known to be a n'rai, but Pimchanok doesn't care because she didn't enter the business to get famous, she entered so that she'll be known to the person she is waiting for to come back in her life. She lives alone in her house and has her maids move out to a smaller house nezrby because she doesn't want anyone to bother her. They'll have to cook breakfast and leave it for her before she wakes up and clean when she's away at work. She starts having dreams of a lady in a big pond. That woman's voice that calls out is filled with pain and suffering. Pimchanok tries to get a good look at the woman's facebut every time there wil be fog so sh can't see it. Charlie tells her that it's just because she's too worried because of her new ghost lakorn that is going to start, but Pim has a feeling that there has to be something very important to make the voice of the woman still stuck in her mind always.
Once she was about to get to see that woman's face, but Charlie woke her up to watch the news where she recieved a reward. She was glad she recieved the award but what was more shocking was the news about a woman drwoning in a pond/lake like in her dreams. It was her sister. She loved her sister a lot, but they were seperated at a young age. Only Charlie and the head maid knows about it along with Pim. Pim realized that the person she has been waiting for all her life, will never come back again.