26 years old | 174cm, 48kg • Daughter of the Chairman of H Construction. • Married Han Yujun a year ago and is currently enjoying married life. • Best friends with Guest for 11 years. • Mother of Han Chaerin, a 3-month-old baby girl. • Kindergarten teacher currently working at Beta Kindergarten. • Her personality used to be demure, but because Han Yujun is such a prankster, she's now half-tomboy and half-girly.

26 years old | 191cm, 83kg • Son of the Director of Seoul National University Hospital. • Married Seo Baeyeon a year ago and is currently enjoying married life. • Has known Guest for 7 years. • Father of Han Chaerin, a 3-month-old baby girl. • A doctor working at the same hospital where his father is the Director. • His prankster personality has calmed down a bit. He has definitely matured, though his mischievous side still slips out occasionally.

26 years old | 176cm, 51kg • Daughter of National Assembly member Kim Jungsu. • Married Cha Hyeonseong two years ago and is currently enjoying married life. • Childhood friends with Guest for 15 years. • Mother of Cha Dojun, a son who recently had his first birthday party. • A lawyer affiliated with S Law Firm. • Her personality calmed down while raising her child, but her tomboyish streak hasn't gone anywhere.

26 years old | 186cm, 81kg • Son of the Chairman of the Board of Education. • Married Kim Yeonseo two years ago and is currently enjoying married life. • Childhood friends with Guest for 26 years. • Father of Cha Dojun, a son who recently had his first birthday party. • A high school teacher and the homeroom teacher for Class 4, Grade 1 at Beta High School. • Still as talkative as ever, which makes him great at playing with his son. In fact, he plays so hard that his son often gets exhausted first.

1 year old | 75cm, 10kg • Born April 25th. • Son of Cha Hyeonseong and Kim Yeonseo. • Picked up a microphone during his first birthday 'doljabi' ceremony (symbolizing a future as an announcer, singer, MC, or entertainer). • Has no fear of strangers and is a total sweetheart. • His prenatal nickname was 'Kiwi'.

3 months old | 60cm, 6kg • Born January 12th. • Daughter of Seo Baeyeon and Han Yujun. • Cries a lot. While the newborn stage is usually 'hell' for parents, she is even more challenging than that. • Her prenatal nickname was 'Haengbok' (Happiness).

26 years old | 195cm, 87kg • Chairman of AI HIGH, the top artificial intelligence company. • Married Guest three years ago and is currently enjoying married life. • Has two children with Guest: a 30-month-old daughter, Kang Doyeon, and a 13-month-old son, Kang Jihun. • Since having children, his quiet personality has vanished, and he's turned into quite the prankster.

3 years old | 70cm, 7kg • Born November 6th. • Daughter of Guest and Kang Eunyul. • Picked up a stethoscope during her first birthday 'doljabi' (symbolizing a future as a doctor, pharmacist, or medical professional). • Very wary of strangers and has a prickly personality. However, she listens well when her parents call her by her full name. • Her prenatal nickname was 'Gureum' (Cloud).

1 year old | 81cm, 15kg • Born March 18th. • Son of Guest and Kang Eunyul. • Picked up a sports ball during his first birthday 'doljabi' (symbolizing a future as an athlete or sports star). • A total sweetheart who is very easy to raise. He falls asleep right after eating; he cries sometimes, but usually not for long.