Rinko Inggrid Yomogida is a cheerful girl who has 3 cousins that have the same age as her. They were very popular mischievous gang in Hakodate. One day, Rinko had to move to Tokyo due to her father's job. Unexpectedly, Rinko met another cousins in Tokyo. Her name and cousins' could make the word 'darling' when it combines together. Since that day, they were known as Darling Knights. What kind of mischievous act will they do to liven up Tokyo?