Fifteen-year-old Yume Kikuchi travels to Tokyo to begin her apprenticeship as a licensed magic user. Unfortunately, Yume is a country girl in the big city her lack of confidence might jinx her into failure. It will take a lot of helping hands from her fellow students and teachers if she’s going to succeed. But in the end, the most important lesson she’ll learn may not even be about spellcasting. The process of growing up and discovering what lies inside your own heart is the most wonderful magic of all in Someday's Dreamers!
Kikuche Yume arrives in Tokyo and, in her confusion, is almost hit by a car. She meets Zennosuke, who helps orient her and sends her in the right direction to Oyamada-sensei’s office. After realizing that Oyamada is male, she has a bout of homesickness and has a negative second encounter with Zennosuke.
Yume tries to get acclimated, but she cannot stop thinking about Zennosuke. Later, she meets Master Furasaki and Angela Brooks, who is the most powerful mage in Japan. Yume sets out to find Zennosuke and tries to make amends.
A beautifully dressed woman—Goto Ayano—shows up seeking Oyamada’s help, but she is uncooperative and cross. Yume and Angela try to help her, but they end up causing more problems. Oyamada receives sudden but good news.
Oyamada takes a day off with no mention to where he is going. Yume’s latest adventure takes her to the moon for a picnic. Elsewhere, Furasaki indulges in a few too many adult libations.
Yume is invited to Master Chief Ginpun’s home, and her experience is less than stellar. Runa runs away, and everyone searches for her. Although Runa’s mother begs Yume to perform magic to locate her, Yume refuses; the power of mother-daughter bonds proves to be the real magic.
After hearing of three children who nearly drowned and remain in critical condition, Yume, Kera, and Oyamada see what they can do to help. Kera begs Oyamada to save one of the boys who is steadily deteriorating. When he cannot, Kera discovers powers within himself.
Yume, Angela, and Oyamada go to the shopping district, which has been vandalized. They discover that a “street mage” has attempted to fix it already, but his inexperience and lack of self-confidence have caused him to do shoddy work.
Yume unexpectedly faints, and Angela takes her to the infirmary. Later, the girls, along with Inoue, go to Tokyo Tower. Angela and Inoue profess their love for each other.
Angela is suspended from practicing magic for a week. Yume conducts a client interview on her own until Kera crashes it, claiming to be her assistant. The new case puzzles Yume.
Yume’s confidence as a mage is shaken when a client expresses regret about having a temporary spell cast on her house, and she begins to question the value of performing magic.
Ginpun informs Yume that her certification exam will entail using her power on Oyamada. Yume feels disenchanted by magic and her use of it. Details of Oyamada’s past begin to unfold, revealing a clear yet sad portrait of him.
Zennosuke finds the missing Yume and reassures her that her magic is useful and positive. The time comes for Yume’s certification exam, and she does not hold back. She helps Oyamada gain closure at last and passes her exam. She says her farewells but promises to return. Someday.