Cheerful 12-year-old Mayu Kousaka is excited for her first day of middle school until she learns that she has to sit next to Shinya Amamiya in class. Haunted by his rejection of her feelings toward him, she spends that night binging soda at her mother's cafe. Despite her efforts to get over him, she sheds a tear that drops into her cup, changing the soda into a seven-colored drink.

After chugging the drink, Mayu suddenly meets a self-proclaimed "drink fairy" named Pucho, who rages at her for drinking what was supposed to be for herself. Due to Pucho's drink, Mayu now transforms whenever she drinks something—which often results in disastrous effects! Both Mayu and Pucho are now endlessly distressed until Pucho sees that Mayu may still have feelings for Shinya.

To make Pucho's seven-colored pixie pop, a human tear needs to be mixed with seven-colored drops that are gained from feelings of love. The two girls take this as an opportunity for Mayu to try again and win over Shinya; but with Shinya being difficult and Mayu's unpredictable transformations, their quest will not be easy.