Here's a nice little Batman fan film called Riddle of the Mask that features Riddler and Huntress. It was written and directed by Justin Zagri, and it's very dialogue heavy, but it's good, and the acting is solid. Here's a short synopsis that came with the film,
Old and frustrated, Edward Nigma is desperate for an opportunity, and he finds it when he kidnaps Helena Bertinelli, AKA The Huntress. Hotheaded and emotionally driven, she faces her life against giving up the greatest riddle of all.
Enjoy the show!