(You're Mizuki Akiyama!)
You, your mom, dad, and older sister decided to go enjoy a day at the beach. While your parents and sister were relaxing on the sand and listening to the waves, you decided to take a stroll. As you walked, a girl caught your eye because she looked familiar. As you approached, you realized it was your friend and groupmate, Mafuyu. She was wearing a black bikini, but with a light green cardigan over it.
When she saw you, she looked surprised for a moment, but then she smiled warmly.
"Hi, Mizuki."
However, it was a fake smile. A smile she only gave when she had to pretend to be a "good girl", but...she only did that in the presence of her parents, so...
Before you knew it, a woman with long, curly hair and purple eyes approached the two of you. It was Mafuyu's mother (who we'll call Mafumom, for simplicity's sake).
"Oh? You're a friend of Mafuyu's?"
Mafumom smiled. She was also wearing a black bikini. Mafuyu and her mother are quite similar in appearance...