OVA
Description
Yoko Asagiri, a high school student, composes a piano sonata to express her romantic feelings for a classmate yet lacks the courage for direct confession. While listening to her composition on a Walkman, she is unexpectedly transported to the fantastical parallel world of Ashanti, connected to her own world of Noa. This transportation occurs because her love song inadvertently bridges the two realms. In Ashanti, she meets Lingam, a talking dog, who explains the worlds' history of separation by the warrior Leda to protect Noa; her arrival temporarily reopens the connection between the dimensions.

Her Walkman, containing the song, is stolen by forces serving the ruler Zell, who believes it to be the "Heart of Leda" needed to permanently open a portal to Noa for conquest. Evading capture, Yoko falls into a giant insectivorous plant-like flower. This cocoons her and triggers a transformation; she emerges as the prophesied warrior of Leda, clad in distinctive bikini armor. The armor exposes significant skin but provides high defense through energy conversion capabilities, nullifying most attacks and dissipating heat energy as light. It includes shoulder guards, neck padding, elbow-to-wrist gauntlets, and knee-high boots, with a metallic-textured bra and pants ensuring full mobility. As Leda's warrior, she gains heightened intuition, instant comprehension of mechanical systems, combat proficiency, and wields a straight sword that generates a blade from its hilt capable of cutting advanced materials.

Guided by Lingam and a girl named Yoni, Yoko locates the Armor of Leda, a 15-meter-tall transformable mecha shifting into the Wings of Leda ship. Powered by twin Leda Converters, it reaches speeds of 4,520 mph and is armed with laser cannons and machine guns. When Zell's forces destroy Yoni's robot Rubber Star, Yoko pilots the Leda Armor to Zell's floating castle, Garuba. Confronted by Zell, she is psychologically manipulated; he claims her transport resulted from a desire to escape her insecurities. He captures her allies and induces a dream state where she lives out a romantic relationship with her crush. Recognizing this as an illusion, she breaks free, rescues her friends, and causes the portal machine to overload. In the ensuing conflict during the castle's collapse, Yoko kills Zell by stabbing him. After escaping, she returns to her world. Empowered by her experiences, she actively seeks out her classmate to confess her feelings, demonstrating newfound confidence.

Her abilities as Leda's warrior include controlling the "Leda Heart" power through her piano composition and intuitively operating otherworldly technology like aerial bikes and the Leda Armor without instruction. The armor's assembly process varies between media: the OVA shows it pre-constructed in a temple, while the novelization depicts it being laser-cut and assembled from surrounding materials upon activation.