Mint is a girl who happens to be the princess of the world of dreams and magic. The natural environment of her world is a reflection of the dreams of the people on Earth. It is now in danger as people lose faith in their dreams and let darkness enter their hearts. The environment of Mint's world is starting to wither and die. On her 12th birthday, after a gala celebration with her father the King and her mother, she agrees to go to the world of humans to try to preserve people's hopes and dreams, and to prove that she has the qualities necessary to be a wise ruler. Her father arranges for her to stay with his sister, Mint's aunt Herb, who runs a gift shop on Earth called "Happiness Shop".

OVA bundled with the special edition of manga volume 3. Morita Mayu is a high school girl. She is extremely reticent and her silence and habit of looking at people's eyes straightly sometimes cause misunderstanding. The reason behind it is not because she doesn’t like to talk nor because she has nothing to say. The reason she rarely speaks is due to the fact she thinks too much before speaking, thus losing the timing to speak altogether. Despite this, she lives a happy school life with her classmates.

Tomoya Mikami's life changed one day when his girlfriend Ayaka was hit by a car and killed on her way to meet Tomoya. He blamed himself for her death and never was the same after the accident. He began acting callously towards Yue and his other friends. Furthermore, every time Tomoya gets involved with a new girl, he sees images of Ayaka in his dreams. He decides he needs to find a way to say goodbye to his lost love once and for all, while dealing with several side romances at the same time.

Ginya Otonashi is a college dropout who works part-time for a pachislot publishing company while aspiring to become a novelist. One day, Ginya comes across a secret organization and gets pulled into a competition to become #1 in "Pachi Battle," which is all a part of the Slotseum, a pachislot competition.