Eighth film in the DCEU, it is set after the events of Suicide Squad (2016) and follows the life of Harley Quinn (Margot Robbie) post her break-up with the Joker. Upon crossing paths with Cassandra Cain, a young girl who is in possession of a diamond belonging to an evil crime lord known as Black Mask (Ewan McGregor), Harley joins forces with other female superheroes including Black Canary, Huntress and Renee Montoya to protect the young girl.