Faster than a speeding bullet... more powerful than a runaway train... able to leap tall buildings in a single bound! It's a bird, it's a plane, it's Moldiver?! Hiroshi Ozora, a young scrawny inventor, dreams of being a strong and courageous (and don't forget popular) hero. After pulling a tortuous all-nighter, he comes up with the Moldiver unit. Once the unit is activated, it creates an invincible suit around the user and bestows superhuman speed and strength. There's only one problem: the unit wears off after 666 seconds. Oh, there's a second problem too: it destroys whatever clothing the user is wearing, so if the user isn't too careful, he (or she) may end up showing off his birthday suit to the mass public. And there's just one more minor hassle Hiroshi has to deal with: his younger sister, Mirai.

It turns out that Mirai is head-over-heels for the hunky Kaoru Misaki, who happens to be Hiroshi's best friend. (Isn't he dreamy?) But Mirai is a bit too enthusiastic and insists on using the Moldiver unit herself. (Not just to stop crimes but to also win over Mr. Misaki, of course.)

Moldiver's biggest enemy happens to be Machinegal and his crew of young female assistants. Machinegal's goal is to take antique technology (like an F-1 racing car and the space shuttle) into his own custody, where he feels it is safe and appreciated. It turns out that Machinegal is actually Professor Amagi, Hiroshi's former mentor and Misaki's present boss! In this episode, Mirai manages to land a date with the gorgeous Mr. Misaki. But can she make it? More importantly, can she make it alive while being mercilessly attacked by the Machinegal dolls?