Mara Carrow has known Jason Todd all her life. Jason's bright idea to steal the hubcaps from the Batmobile leads to lives neither of them could have ever seen coming; lives as Batman's sidekicks, Robin and Phoenix. But the life of a vigilante comes with a cost, as Mara is about to learn. 

Adelaide Kane as...

...Mara Carrow

"Phoenix"

"I'm regretting your life choices right now, Jason."

Curran Walters as...

...Jason Todd

"Robin"

"We're not in trouble and we get to be Batman's sidekicks! What's to regret?"

Henry Cavill as...

...Bruce Wayne

"Batman"

"The two of you are not my sidekicks. Not yet. "

Dylan O'Brien as...

...as Dick Grayson

"NIghtwing"

"Couldn't you use some name other than Robin?"

with 

Ian McKellen as Alfred Pennyworth 

 Zoe Kravitz as Selina Kyle/Catwoman

and others as described