Place: Gotham City
Conditions: A rift in time has plucked all three Robins from their respective timelines and has placed them in an abandoned factory somewhere in Gotham City. Escape is impossible, as there are no doors or windows. Blasting or cutting through the walls is also impossible, thanks to some magical force.
It doesn't matter when they are, all that matters is who and how old they are.
Robin I: Dick Grayson is 15 years old, and is still Batman's jovial sidekick. Little does he know of his future self -- Nightwing. Thinks the other two are evil imposters, and fights to prove it.
Robin II: The angry, rash Jason Todd is alive and well, and also in his mid-teens. He knows that Dick and Bruce had some sort of falling out and that Dick would later become Nightwing, but this does little to serve him as he's too impulsive to use it to his advantage. Doesn't care who the other two are, he just wants to fight.
Robin III: Tim Drake (16 years old) has one up on his predecessors, in that he realizes who they are and knows their fighting styles. Unlike Jason Todd (who may or may not know that one of them is Dick Grayson), Tim uses this to his advantage. He fights to 1) protect himself, and 2) stop the scuffle so they can find a solution to their mutual problem.