Director Cathy Yan's superhero action-drama is a spin-off of 2016's "Suicide Squad". It stars Margot Robbie, Mary Elizabeth Winstead and Ewan McGregor. After deciding to operate independently of the Joker, Harley Quinn (Robbie) teams up with Black Canary, Helena Bertinelli, and Renee Montoya to save a young girl from a contract killing that has been initiated by a brutal and narcissistic Gotham City crime lord (McGregor).