Who could Godzilla's new mysterious foe be?!
He's probably the most Evil,
... Oh, alright, it's King Ghidorah again.
Once upon a time, in the unfortunate land known as Tokyo, Japan, aliens (known as the Xiliens) arrive. It turns out that when Godzilla & Friends drove King Ghidorah back into space, he ended up flying to THEIR planet (Planet X). Generally, they want to borrow Godzilla and Rodan to defeat King Ghidorah (Mothra's in her cocoon at this moment) and in exchange, they'll give us a cure for all known diseases. Freakin' sweet! Naturally, they accept the offer, and the Xiliens ship off Godzilla and Rodan (who's also in the ocean... for... some reason...) to Planet X, to do battle with Ghidorah. Even without Mothra, Godzilla and Rodan quickly defeat Ghidorah with their combined efforts. After that, Godzilla performs the best victory dance ever (you'll have to see it to believe it):
A happy moment indeed. But happiness does not remain for too long... it turns out that all along, this was a ruse by the Xiliens to take over the Earth (But then again, who DIDN'T see that coming?), because they don't have any water. It turns out that shortly after King Ghidorah had arrived on Planet X, they took control of him, dubbing him Monster 00 (which explains the title). Now that Godzilla and Rodan are on their turf, they put them under their control as well (with the Xiliens referring to them as Monster 01 and Monster 02, respectively, due to their naming system consisting entirely of numbers). As such, they unleash Godzilla, Rodan, and King Ghidorah to wreak havoc on the Earth. Geez... if they really need water THAT bad, couldn't they just borrow some from us? Well, anyhow, the monsters start their rampage on the cities of Japan (making wonder how there's actually anything left to destroy). All seems lost... and seeing as Mothra won't be coming out any time soon, Nick Adams saves the day! He and his friend... some-other-guy destroy the source that's taking control of the monsters, as well the Xiliens' spaceship. Planet X then decides to withdraw its invasion of Earth, as Godzilla and Rodan kicks King Ghidorah's ass again. King Ghidorah might as well be called "Puss Ghidorah" by now, because this is the THIRD time that he's retreated into space. Man...