Fei Fei, a young girl with a vivid imagination, begins her story by listening to her Ma Ma, [Ruthie Ann Miles], recount a charming legend about a giant space dog that eats the moon, causing it to appear in different phases. She also learns about the moon goddess, [Phillipa Soo] as Chang’e, who once lived on Earth with her lover, Houyi. According to legend, Chang’e took two immortality pills and ascended peacefully to the moon, leaving Houyi behind to face loneliness and longing. She now resides alone on the moon with only her loyal Jade Rabbit by her side (“On The Moon Above”).
The story shifts to Fei Fei’s everyday life on Earth. Her father, [John Cho], who owns a mooncake shop with her Ma Ma, is preparing for the Moon Festival, a traditional celebration that holds deep cultural significance. During this time, Ma Ma begins to fall ill but remains hopeful and nurturing, especially to Fei Fei. As a heartfelt gift, Ma Ma gives Fei Fei a small bunny, Bungee, which the girl names after her favorite creature. Tragically, Ma Ma passes away, leaving Fei Fei devastated but determined to keep her spirit alive.
Over the next four years, Fei Fei, now a curious and resilient girl, helps her father run the shop and continues to dream about the moon. She notices her father, Ba Ba [who runs the shop], beginning to see another woman, Mrs. Zhong [Sandra Oh], which prompts her to realize her father is moving on from her mother. Fei Fei also meets Mrs. Zhong’s son, Chin [Robert G. Chiu], who owns a frog named Croak and believes he has the extraordinary ability to phase through walls, adding a sense of wonder to her life. Her relatives, including Aunties Ling and Mei, Grandma, and Grandpa, arrive for a family dinner, and the Moon Festival is celebrated with joy, but Fei Fei’s heart is heavy because she views Chang’e as a symbol of eternal love, waiting on the moon for her Houyi.
During the family gathering, Fei Fei becomes upset when the adults diminish the legend of Chang’e, claiming she is just a myth. She causes a stir by pulling the Lazy Susan, spilling food and passionately insisting that Chang’e is still waiting for her lover. She believes that her father could wait for Ma Ma again if he could be reunited with her return. When she learns that her father and Mrs. Zhong are already engaged, Fei Fei feels hurt and angry about the idea of having a new “brother,” Chin.
Feeling overwhelmed by her emotions, Bungee hops out of the window, prompting Fei Fei to follow her outside. The rabbit leads Fei Fei to a crane — a symbol from Chang’e’s legend. Looking up at the moon, Fei Fei feels inspired and decides to build a rocket that can take her there with hopes of proving her father could reunite with his wife someday. With determination, she crafts multiple prototypes, drawing inspiration from the magnetic levitation train being built in her town, called “MagLev.” After much effort, Fei Fei finally completes her rocket and, along with Bungee, embarks on her journey toward the moon.
However, shortly after launch, the rocket’s engines falter, causing it to start falling back to Earth. It turns out Chin secretly stowed away on her craft, adding weight to the spaceship, putting their mission at risk. Just as the situation seems hopeless, a beam of mysterious light from the moon draws them in, pulling the rocket onto the lunar surface. When they arrive, they are greeted by flyling lion creatures who take them to the moon kingdom of Lunaria. There, Fei Fei and Chin encounter three lively mooncake creatures called Lunettes and meet Chang’e herself, who performs a dazzling entrance song ("Ultraluminary") that captures the magic and extravagance of her realm.
Unlike the kind and gentle goddess Fei Fei expected, Chang’e appears vain and somewhat self-centered. She initially believes Fei Fei’s visit is motivated by a desire for a special gift that will allow her to see Houyi again, and she intends to trade a picture of Fei Fei for that gift. Chang’e announces to the Lunarians that if they find this mysterious gift, they will be granted wishes too, igniting a frantic search across Lunaria. Meanwhile, Chin, eager to prove himself as a brother, tries to gain Chang’e’s trust but is met with her skepticism. She challenges him to a ping-pong match ("Hey Boy") in a test of his sincerity. Despite her efforts to keep him at bay, Chin ultimately calls out her loneliness and selfishness, exposing her deep desire for companionship and love.
Fei Fei, with the help of the Lunettes, sets off to retrieve the gift from a crash site on the moon. There, she discovers a small moon dog named Gobi [Ken Jeong], who once served in Chang’e’s palace but was exiled by her. The girl finds a doll that belonged to her mother, believing it to be the sought-after gift. As Gobi and the others ride away with it, Fei Fei chases after them but faces giant moon frogs that try to attack her. Using Gobi’s stretchy tongue, she lassos a moon frog and seizes the opportunity to ride it back to Lunaria. There, Gobi sings a heartfelt song (“Wonderful”) about the unbreakable bond of love and the importance of companionship even when loved ones are physically apart.
Although Chang’e mourns her loneliness and fears she will never see Houyi again, she begins to grow despairing. Her tears, which are sentient, reveal that they form the core of Lunaria, and her uncontrollable emotions could cause catastrophic events like meteor showers. Meanwhile, Bungee encounters Jade Rabbit, who is working on a potion to help Chang’e reunite with Houyi. Bungee later gains some of his powers and shows romantic interest in Jade, which he reciprocates.
As the group nears Lunaria, Fei Fei rushes after the chickens carrying the doll. During a struggle over the doll, it shatters upon contact with a beam of light, leaving Fei Fei disappointed but still hopeful. She then notices a piece of moonstone embedded in her mother’s mooncake, which matches with another half she finds on the moon. Recognizing it as the true gift, she and Gobi race back to the palace. Chin, despite initial doubts, manages to break through the barrier surrounding Chang’e and joins Fei Fei inside. Using the halves of the moonstone and Jade’s potion, they reunite Chang’e with Houyi (“Yours Forever”).
Their moment of happiness is brief, as Houyi must return to his realm, leaving Chang’e heartbroken. Though she admits that their love is eternal, she must now learn to move on. Her intense sorrow plunges Lunaria into darkness, trapping her in an emotional realm where her own tears threaten the universe. Fei Fei enters this realm to comfort her and faces a haunting vision of losing her mother again. With kindness, Chang’e discovers that even though her physical body is apart from Houyi, her spirit can find peace and new happiness. She encourages Fei Fei to cherish new relationships, including Chin, and to accept love in her own life.
With her tears transforming into a source of hope, the Lunarians brighten as Chang’e finds inner peace. She thanks Fei Fei for reminding her of the importance of love and companionship. Before leaving, Chang’e gives Fei Fei the cherished photo, symbolizing her gratitude and the love they shared. Though the photo burns during re-entry, the warmth of their bond remains. Fei Fei returns home, carrying Chin on her back, with her heart feeling lighter and more open to new beginnings. Ba Ba later marries Mrs. Zhong, and the family celebrates the Moon Festival together. As they enjoy the festivities, Fei Fei notices a crane — a sign that Chang’e may still pay her a visit, while Chin and her prepare for future adventures and friendships, completing her journey from loneliness to hope and connection.
