Seo Ji Won (Jung In Sun) is a budding web-based cartoon author who decides to devote her undivided attention to her craft – forsaking love in favor of her career. And her decision pays off. By the time she is 25, she is a published author. Now, aged 30, she has become a well-recognized writer with scores of devoted readers. But turning her back on romance turns out to be harder than she first thought when Lee Seung Yoo (Kang Min Hyuk), her first love from her middle school days, returns to the scene to turn her world upside down. And things get more complicated when the film director Cha Do Hoon (Song Jae Rim) – who has been charged with adapting Seo Ji Won’s web-based series for the screen – confides in her and appears keen to strike up a close friendship. Meanwhile, Seo Ji Won’s best friend, a one-time TV anchor named Lee Ran Joo (Hani) is having a hard time adjusting to “normal” office life in her new career. “How to Be Thirty” is a 2021 South Korean drama series that was directed by Oh Ki Hwan.