Lionsgate has released the first trailer for A Simple Favor. Anna Kendrick stars as a woman whose best friend (Blake Lively) goes missing. As she tries to figure out what happened to her, Kendrick's character begins to realize that perhaps her "best friend" was not the person she thought she was. This looks like more of a mystery thriller rather than a comedy, but director Paul Feig has a stellar track record for crafting great movies about strong female characters (Bridesmaid, The Heat, Spy). A Simple Favor opens September 14.