The humans emerged from the Antarctic base in a panic because King Ghidorah was erupting from the Earth itself in an orgy of geographic destruction. They barely mattered to the behemoth and it was only due to the intervention of a kind and loving god that the humans were going to get out of there alive. Or, in this case, a kind and loving Godzilla.
As Godzilla rushed forward to join King Ghidorah in combat, something fell from the heavens: it was Matsu Her-O in his mech, the Gladius. The Gladius threw out its hands to keep the two kaiju at bay and then Matsu ejected from it, the mech's job done. He took careful stock of both monsters and decided that, while King Ghidorah was more powerful, Godzilla was far better suited to joining Matsu on his quest and so Matsu powered up and took out King Ghidorah with what he called the Matsu Combo: a punch, a kick, and an energy blast which disintegrated the monster fully. Godzilla didn't even hesitate as he bowed to Matsu, his new king.
Matsu landed and ignored the humans who were even now coming towards him, and only paid attention to the new arrival: Pokemaster Terrapin. Matsu told him, "It's up to you get our new creature on the ship. I have a meeting to get to, and also have to figure out how to power up my mech. It didn't perform very well today."
Matsu vanished, teleported back onto the ship, leaving Terrapin to deal with the aftermath. The Pokemaster looked up at the hulking form of Godzilla and felt terrified and a little dizzy. He had a job to do and took out an Ultra Ball. He tossed it once and then lobbed it at Godzilla. It bounced off his thick hide and rolled back towards Terrapin.
"Well, I'm out of ideas," he said, to no one.
On the ship, Matsu Her-O hurried towards his drawing room where some of the greatest investigative minds across the Fictosphere had been summoned. Batman, already a resident on the ship, was there. L, who had pursued Kira and the Death Note, perched on a chair eating a candy bar. Sherlock Holmes practiced his violin and kept shifting his form to match his many versions. Darkwing Duck was trying to get people to listen to one of his adventures. Dick Douglas, of the Basset Hound Brigade, was deep in thought. Hercule Poirot was there, too, along with Nancy Drew and the Hardy Boys. Columbo and Jessica Fletcher each seemed eager to crack the case. Charlie Chan seemed naked without his clan, and was trying to strike up a conversation with Dick Tracy. There were also other theres, so if your favorite wasn't mentioned they were totally there but I've already named like fifteen people so just take it on faith that they were there. When Matsu entered, they all turned to him.
"I suppose you're all wondering why I called you here today," said Matsu.
"I'd imagine it's to solve some sort of mystery," said Batman.
"One which the great Matsu Her-O can't solve by himself, so it's likely not concerning anything terrestrial," added Sherlock.
"Something dangerous enough to pull us each from our various worlds and times," posited L.
"The fact that he had to add all of you instead of just settling for me must mean it's something big," said Darkwing Duck.
"You're all right," interjected Matsu, who didn't want to sit there listening to detectives all day. "There's a man out there who's proven to be my equal in every way and I need to find out who he is."
"Jeepers," said Nancy Drew.
"If someone's that bad," said one of the Hardy boys, "We'll do all we can to help!"
"I'm glad you said that." Matsu raised a hand. "I'm just going to absorb your detecting prowess so I can figure out what's going on."
Dick Douglas, shaken from his thoughts, said, "Wait, what?"
"Only a little from each of you, so while you'll still be your world's foremost detectives I'll be the greatest detective in the Fictosphere," clarified Matsu, and before anyone could protest Matsu's fist lit up and each of the detectives felt some of their investigative powers dwindle ever so slightly and the cumulative effect allowed Matsu to realize the identity of his antagonist.
"I've got it," he said, grimly.
Dick Tracy moved forth, as if to accost Matsu, and then thought better of it, simply waving his arm and shourting, "DOn't leave us in suspense. Who is it?"
"It's safer if you don't know," said Matsu, and he transported a lot of the detectives back to their homes but kept Batman, L, and Darkwing Duck. He told them, "You'll be useful as part of my crew."
He then walked out of the room, eager to put his newfound knowledge to good use.