Park Jihyo is an acting CEO of a famous pay telivision music Channel in Korea, who also appear to have a daughter at a young age. She's known for being workaholic and strict CEO as well as a mother. Park Tzuyu is the name her five year old daughter. 

Tzuyu is a good, well-mannered and smart kid but still afraid of her mom. She's used to be alone since her mom is always busy. Her mom made a rule, Mommy saysㅡ if her mom told her that, she needs to obey no matter what comes in the next sentence.

Hirai Momo is a famous dancer and choreograher together with her duo Myoui Mina. She's lazy and really do hates working but she's a gifted dancer so she doesn't have a choice. Her world seems to become so boring for her not until she met Tzuyu, Jihyo's daughter.