Disclaimer: me no own thanks
This will be an AU so don't get angry with me.
The basis is from the three movies not the animated series
Prologue
Plain Shift
It was a warm summer day in the bustling city of New Work, since the disappearance of the renegade gang known as the foot clan, the streets have been pretty peaceful as of late. This newfound peace has left our four green heroes with not much to do but sit around their abandoned train station. The only one not just sitting around was Donatello, he as usual was tinkering around with his many scientific experiments. The one he was currently working on was one that might open a rift in the very fabric of reality or it might make a very bad cup of coffee no one really knows not even Donatello. After a few months of planning, plotting and sketching he was ready to begin building his machine. Three months was spent gathering the needed parts, followed by two more months of painstakingly slow work putting it all together, finally the machine was done.
"Hey guys, come check out my invention it's a new pizza maker so we don't have to order out all the time." Don shouted at his three brothers. Leonardo, the oldest, stopped his morning training exercises and walked to Don's room. Raphael the second oldest, snorted and followed Leo, and Mikey, the youngest took his pizza to go and joined his brothers. "Well here it is" Don says pulling the sheet off the rather large contraption. The machine was unusual looking to say the least, not even close to what a pizza maker would look like. "Let's fire this thing up I am hungry" the jovial voice of Michelangelo. Donatello flips the switch to turn it on, the machine whirls to life with loud obnoxious noises. As the machine warms up something goes horribly wrong, the large machine begins to emit a thick black smoke a large bang is heard followed by a flash of whitish light. The last thing the brothers hear before darkness takes them is a soothing voice telling them it will be alright. Back at the train station, when the black smoke clears, there is no trace of the turtles anywhere.