Hyoyeon and Eunhyuk have been together for 4 years since grade 10. They were known as the 'it' couple, everyone thought that they were perfect for each other. Even Hyoyeon and Eunhyuk thought they were meant to be; never fought, argued, nothing. They were always happy, but until Hyoyeon found out she was pregnant. No one new about her pregnacy except her family. She was going to tell Eunhyuk, but she also found out the he was cheating on her for the past 7 months. She decided to move to California with her cousin and sister so she could protect her child from getting hurt like herself. 

6 years of living in California, Hyoyeon finally decides to go back to Korea, not because she was forced to but because she wanted her son to know about Korea and also to know her close friends, plus her sister, Taeyeon was switched to a music company in Korea. The only thing she was afraid of was her son meeting Eunhyuk and eventually, he did. Eunhyuk did everything he can to get closer with Hyoyeon and his son, but he couldnt do that because Hyoyeon was always stubborn and wont let him get too close with her and especially her son and also because of Gyuri, his ex - girlfriend. But Eunhyuk doesnt care how long or what it takes, he just wants his son to know him and especially to get Hyoyeon back. 

Kim Hyoyeon

-  Got pregnant at the age of 19
- She's now 25 years old. 
- Mother of Kim Jongin, also known as Kai. 
- Even though she's a mother, she's still the same stubborn and childish Hyoyeon.
- She always loves to dance. 

Lee Hyukjae or Eunhyuk 

- Father of Kim Jongin also known as Kai. 
- He's 26 years old. 
- Completely changed from fun, outgoing, and immature to serious, protective, and workacholic person. ( When Hyoyeon left. ) 
- Still loves Hyoyeon and wants her back. 

Kim Jongin also known as Kai

- Son of Hyoyeon and Eunhyuk
- Loves to dance.
- 6 years old. ( Ehe, pretend he's six.. )
- Chidish, shy, and cute.

Kim Taeyeon                                                              Jung Jessica

- 26 years old.                                                               - 25 years old. 
- Older sister of Hyoyeon. Aunt of Kai.                      - Cousin of Hyoyeon and Taeyeon. Aunt of Kai.
- Protective towards her family.( Hyo, Kai, Sica)     - Protective towards her family and friends.
- Childish, good at singing.                                         - Immature, Loves to play jokes on Kai.
- Engaged to Wooyoung                     

Lee Donghae                                                           Lee Soon Kyu also known as Sunny

- Cousin of Eunhyuk and Sunny                                     - Younger sister of Eunhyuk. 
- 25 years old.                                                                     - 24 years old. 
- Childish, jokes around, sensitive but strong.              - Bestfriend of Hyoyeon, but doesnt know abut Kai and her arrival in Korea.
- Moved from China when he was 20.                            - Immature, sweet, and bubbly.
                                                                                               - Hasnt been talking to Hyo since she left. 

Choi Sooyoung                                                                                          Jang Wooyoung                                             

- Bestfriend of Hyoyeon.                                                                        - Engaged to Taeyeon.                            
- Doesnt know about Kai and her arrival                                             - 26 years old.                                            
- 25 years old.                                                                                          - Met the Kim family in America.             
- Protective, fun, and supportive towards Hyo.                                  - Protective, supportive, and childish.   
- Hasnt been talking to Hyo, when she left. 

Choi Siwon                                                                        Park Gyuri

- Older brother of Sooyoung                                         - Ex- girlfriend of Eunhyuk
- Bestfriend of Eunhyuuk                                                - 26 years old
- 26 years old                                                                   - Hates the Kim family
- Protective towards Sooyoung , worries about         - Rude, annoying, and gets what ever she wants no matter what
  Eunhyuk a lot.