Its based of the movie

you, the turtles, april and splinter are really close friends but one day you fight the foot clan because they wanted to steal a startur like thingy, you stoped them but as raph was about to catch the thing leo bumped into him and the foot clan had it again as they left.

[Time skip]

back at the base OUT OF NOWHERE chaesy spawns and you guys tie him to a chair. As he wakes up he seems pretty nervous but still confident