I Have a Wonderful Little Sister

"There are four little bears living together. A bear dad, a bear mom, a bear big brother, and a bear little brother. Bear Dad is chubby, Bear Mom is slender, Bear Big Brother is mischievous, and Bear Little Brother is adorable. Then one day, a baby bear was born. The baby bear was so adorable. Whoop, whoop, how wonderful! There are five little bears living together, growing up day by day~"

The big brother is Kim Seokjin. The female lead is his younger sister, seven years younger. The male lead is undecided.

Theme: Growing up means becoming a better person.