Every day, a young girl wearing a mask stands by the beach and sings a nostalgic melody. After experiencing two sudden heart-wrenching partings when she was only a child, Nino Arisugawa has been singing her songs to the ocean, bound by a promise made with her two childhood friends—her first love, Momo Sakaki, and a boy who composed music, Kanade Yuzu Yuzuriha. Having never met each other, the boys both individually promised that if Nino was ever separated from them, her voice would be the beacon to reunite them once again. After six long years, destiny has finally placed Nino, Momo, and Yuzu in the same high school. However, the passage of time has changed many things in their lives—while Nino relentlessly attempts to fulfill her childhood promise with the boys, Yuzu's feelings for her from the past resurface, and Momo goes to great lengths to prevent a reunion with Nino. Through music, will they be able to mend their friendship and overcome all the feelings involved in this complicated love triangle?

Two years ago, Mitsuki Kouyama's friend, Eichi Sakurai, moved to America before she could confess her feelings to him. Though she cannot contact him, they made a promise to fulfill their respective dreams: Mitsuki wants to become a professional singer, and Eichi an astronomer. She hopes that one day her music will reach him across the world with a brilliance like that of the full moon. There is just one catch: Mitsuki suffers from throat cancer, which makes her voice quiet and singing strenuous. Her grandmother, who has a hatred of music, insists that Mitsuki undergo surgery to remove the cancer, but she refuses due to the risk of losing her voice. One day, two shinigami—Meroko Yui and Takuto Kira—appear to tell her that she only has one year left to live. This sudden revelation spurs Mitsuki into action, and she decides that with Meroko and Takuto's help, she will become a professional singer in the time she has left. Full Moon wo Sagashite follows the emotional story of Mitsuki and her shinigami friends as they discover what it means to sing—and ultimately, what it means to live.

After Tamahome is reborn into the real world as Taka Sukunami, it does not take long until he meets Miaka Yuuki again, leading to their romance blooming once more. However, the appearance of Ren Shigyou—a new student at Miaka's high school—disturbs their blissful days. Resentful of the happy lovers, Shigyou uses his unusual manipulative skills to quickly become popular and rally his classmates against Miaka and Taka. As Shigyou's followers unexpectedly attack the pair, the two end up falling from the school's roof into a red light and are transported to The Universe of the Four Gods realm. Returning to the place where Taka once lived as Tamahome, the couple learns that an evil demon is behind the recent events. To make matters worse, Taka risks disappearing from existence unless he recovers his previous life's memories, which are stored in seven jewels. Joining forces with their former companions, Miaka and Taka embark on a quest against the clock to retrieve the precious stones before it is too late.

After losing her mother in a tragic car accident, nine-year-old Melmo Watari now faces a big challenge: taking care of her two younger brothers, the preschooler Totoo and baby Touch. Watching from Heaven and concerned about her kids' terrible situation, their mother decides to appear in their lives one last time as a ghost and give Melmo a jar full of magical candies. The candies have the power to make her 10 years older or younger, as well as turn her into any animal she wants. Using her newfound abilities, Melmo wears various disguises as a 19-year-old woman and looks after her brothers, all while still trying to lead a normal life.