Son Chaeyoung, an art student, whom was invited to be taken part of an exhibition. 

Trying to think of an inspiration, she went to purchase her favorite snacks at a convenience store where she met a woman and was captivated by her alluring beauty. While observing her carefully, Chaeyoung noticed that the lady's moles resembles a constellation named Cassiopeia. Up to her own suprise, her feet just started to walk on their own heading straight to the said lady. Without any shame, she introduced herself and asked her to be her model for the art exhibit in which the woman surprisingly agrees. 

Chaeyoung couldn't take her eyes off of her. It just seemed like the woman casted a spell on her that if she ever takes a glance away, she would cease to exist. Is she a witch? A fairy? A goddess? She couldn't care less. 

"Do you know Cassiopeia?" Chaeyoung suddenly blurted out. "It's my favorite constellation. If you connected those moles on your face it would look just like it."

"How did you know about it?" the woman then asked, looking so confused.

"Besides taking an art course, I used to study astronomy with my brother."

Chaeyoung invited the woman out stargazing that night despite just knowing each other in which again, the lady agrees.

Sitting side by side by the hill, away from the city, Chaeyoung showed the young woman where Cassiopeia is located at under the sea of stars. It was a quiet night. They were quietly gazing up at the stars. It was quiet, but had a comfortable feeling. Not until Chaeyoung noticed one of the stars that connects Cassiopeia unusually started flickering. At the same time, she heard the other woman groaning in pain. At Chaeyoung's surprise, one of the woman's moles was flashing at the same time as the constellation's star. It was a whole minute until the flickering stops. Chaeyoung couldn't do anything. She was frozen at her place, trying to process what just happened. She couldn't even moved an inch.

"...What are you?" Chaeyoung in deep shock.

A long pause before the woman replied, taking a long deep breathe at first.

"I'm Cassiopeia and I'm looking for my dear Andromeda, but my time is running out. We were banished from our kingdom. If I am not able to find them until all of my stars disappear, so would I. I'm dying... Please... I need your help."

What has Chaeyoung gotten herself into?