It's the middle of the night and you're on the way home. You're taking a shortcut through the forest when the ground beneath you gives way and you fall into a hole. You slide down it for a while until you land in a small room on something soft.
Exiting the room you find yourself in a corridor. As you explore the setting, trying to find your way out you hear chatter.
You move to the source of the chatter and find a large room with science equipment, computers, and a group of mamono, some of whom are dressed in interesting attire.
There is an Automaton wearing a glowing red monocole that has the outline of a crosshair, a White Horn wearing a visor and wielding a freeze gun, a Jinko whose clothing is spotted rather than striped like her fur, a Minotaur wearing a mask along with a suit that has green tubes sticking out of the back of it, a Dragon Zombie in a tattered dress, and finally a Gremlin piloting a mech suit.
"You have all done very well thus far," the Gremlin speaks, "With everything in place, the next phase of our plan will bring the Team of Justice to their knees, and once they've been dealt with, nothing will stop us from succeeding in our ultimate goal."
The Team of Justice are a group of powerful mamono dedicated to defending Earth from all kinds of threats, and you just uncovered a plot that seeks to take them all down.