Long Story Short:
PPG caught in an interdimensional rift amongst different universes and are somehow transported to the X-men universe in older bodies and new uniforms. Geddit yet?

Buttercup, also separated from her sisters, wakes up in a dumpster--angry and smelly. She soon witnesses a young mutant being beaten up by some stereotypical neighborhood bullies, and naturally steps in. Before she can make a move, another hero arrives on the scene--7, a mutant and leader of a group pf morlocks who live in an abandoned railway station. They kick ass, and bring the young mutant to the station. Buttercup tags along, curious about 7. She is saddened by the pathetic state of the morlocks.

"7, what is this place?"

"My home Buttercup."

Whoever wants to color *pfft!* may go ahead. Just link me back. *doublepfft!*

Buttercup(c) Cartoon Network