Jo Jae-mi is a central character in "Mr. Plankton." Known as the world's unluckiest woman, Jae-mi's life is filled with a series of unfortunate events and mishaps. Despite her constant bad luck, she is resilient and resourceful, managing to navigate her challenging circumstances with determination and a touch of humor. When she meets Hae-jo, she is initially reluctant to join him on his journey, but she eventually agrees. Throughout their journey, Jae-mi's character shows growth as she forms a meaningful connection with Hae-jo and learns to find hope and strength in the face of adversity. Her interactions with Hae-jo bring out her compassionate and supportive side, revealing a deeper layer to her character beyond her unlucky exterior.