When their son Wocky Kitaki was shot in December 2025, Winfred and Plum became worried about what the gangster life was doing to him, and they began to discard the mob life in favor of a more honest one, much to Wocky's dismay. Among their contributions to the city was People Park, which was across the street from Kitaki Mansion. Pal Meraktis, a doctor who was close to the family, was meant to remove the bullet from Wocky's body, but he was unable to do so, and he hid this fact from the family. Half a year after the shooting, Winfred ordered a family checkup with a different doctor and found out that the bullet was still lodged near Wocky's heart, and so he strove to raise honest money for an operation from a doctor who could do the job. Meanwhile, Pal Meraktis was murdered in People Park, and Wesley Stickler stole Plum's bloomers in his efforts to figure out the mystery of Trucy Wright's "magic panties". Wocky was accused of the murder and put on trial.
During the investigation of Meraktis's murder, Apollo Justice stopped by Kitaki Mansion because Phoenix Wright had been hit by a car there. Justice was reluctant to talk with Plum due to her position, but his assistant Trucy Wright did not let this get in the way of a friendly chat. Plum told them about the murder and her stolen bloomers. The following day, Justice found the bloomers and met Plum again to return them. However, she let him keep them as evidence. She also told them about Alita Tiala, who had gotten engaged to Wocky right after his shooting, though it seemed as if she had an ulterior motive. It turned out during the trial the following day that Tiala was Meraktis's nurse and that she had killed Meraktis.
The surname "Kitaki" (北木) literally means "north tree", but the family is also visually linked to "kitsune", the Japanese word for fox and a common subject of Japanese folklore.
"Koume" (小梅) literally means "little plum" in Japanese. The design on her kimono and bloomers contain plum blossoms, which are regarded as a symbol of late winter or the start of spring, and as a ward against evil.
The kanji on the back of her bloomers appears to be "極", whose many possible translations include "highest rank", "forbidden", and "extreme end".