A dying species, the Noza, searches for a new planet to colonise, eventually arriving at Maris, a human settlement. Without time to spare and with far superior technology, the Noza invade Maris to wipe the humans out. When the situation seems hopeless for the humans, three mysterious weapons are found, named "Zillion", powerful enough to cope with the invading Noza army. Being a very limited resource, three top soldiers are chosen to carry the Zillion pistols, codenames Apple, Champ and J.J.
The production adopted a "the simpler, the better" philosophy for the anime series. Except for J.J., little back story is given to any of the characters, the scripting preferring to focus on the characters' development after the team, named The White Nuts, is assembled.
The plot is, indeed, simple, with a classic alien invading force and a struggling human population, although, for a change, that population is not on Earth, but on a far away colony, which the story never bothers trying to explain how it got there. By the way, the story never bothers about how the aliens also got there and why they had no alternative but to invade the human colony planet and engage on a lengthy war, instead of searching for another place to settle. The lack of background doesn't spoil the fun, though, as the characters are very charismatic and the show sticks to the rules it defines for itself, with a few interesting twists that keep it from getting staled.
The graphism of the series is nice, well drawn and animated, although some sequences are reused along the series, like the departure of the main VTOL transporter "Big Porter" and the transformation of the tricycle "Tricharger" into a versatile mechanical battle suit (AKA "mecha"). Again, that doesn't spoil the entertainment value of the show, as everything is carefully well done.
Highlight must be given to the amazing series' soundtrack, composed by Jun Irie, and the opening and ending theme songs, by Yoshiaki Ohuchi, "Pure Stone" and "Push!".
Even though J.J. hints a few insinuating jokes at Apple through the series, "fan service" is mostly avoided, what is a good thing. All comedic reliefs are played well and not overdone. Clichés like romantic drama and unbeatable/invincible protagonist are also avoided, making this show really entertaining.