Yoko Asagiri is a gifted pianist who composes a heartfelt piano sonata to express her love for a young man. While listening to the piece on a Walkman, she passes by the object of her affection, too afraid to confess her feelings. In that moment, the world around her shifts and she is pulled into a fantastical realm. There, a friendly talking dog greets her, and as they converse she notices a shimmering reflection of her own world high above in the sky. It becomes clear that the haunting melody has a strange power: whenever the song plays, she can travel between these two worlds.
Her escape is interrupted when strange riders on mechanical creatures seize her Walkman and attack her. In self-defense, Yoko undergoes a dramatic transformation, becoming a powerful sword-wielding warrior who fights off the assailants with swift, shimmering strikes. After the danger passes, she encounters a young girl named Yoni, who explains that the floating castle Garuba nearby is ruled by Zell, an evil man who uses Leda’s power to push his own agendas. Zell’s ambition is not merely conquest; he seeks to open a portal to the world of Noa in order to dominate it.
Yoni becomes Yoko’s guide in this strange land, leading her to a towering robot known as the Armor of Leda. This colossal machine has the astonishing ability to transform into a ship called the Wings of Leda, offering them both mobility and firepower for the looming conflict. The floating towers that support Zell’s rule unleash a brutal assault, and during the battle Yoni’s own giant robot, Rubber Star, is destroyed. Undeterred, the two allies mount a daring escape and press onward toward Zell’s fortress.
The journey culminates as they reach Zell’s castle, where a fierce confrontation unfolds. Zell erects a force field that isolates Yoko from her friends, and he coldly explains that she came to this world because she wanted to escape her own. In a cruel twist, Zell captures her companions and puts Yoko to sleep to co‑opt her into operating the portal machine. While asleep, Yoko’s dreams replay her love for the young man; in these visions she speaks to him, but the illusion offers no real solace. Realizing the life she longs for is a fantasy, she breaks the spell, rescues her friends, and disrupts the portal device as it overloads.
Enraged, Zell lunges at Yoko, and she pierces him with a decisive stab, ending his reign of terror. With Zell defeated and the castle beginning to crumble, Yoko and her friends escape the collapsing stronghold. The world behind her calls once more, and she finally finds her way back to her own world. In a final test of courage, she spots the very boy she loves and takes off after him, compelled to speak honestly and see where life might lead beyond the fantasy.
