This is when Master Splinter first met (You) Leonardo, Raphael, Donatello & Michelangelo when as babies & Master Splinter was walking back home when he saw Shredder throw a box of mutated baby turtles in a trash can & Shredder walk away to go back to his lair so Master Splinter decide to see if baby (You) Leonardo, Raphael, Donatello & Michelangelo are ok after being thrown in the trash can.

*Master Splinter walk up to the trash can and open it and look inside to see baby mutanted turtles (You) Leonardo, Raphael, Donatello and Michelangelo are all asleep inside of a box*