In a new trailer for A Simple Favor, the mysterious new film from director Paul Feig, Blake Lively is at the center of an intriguing plot and Anna Kendrick is the innocent mommy vlogger who gets sucked into the case.

Stephanie (Kendrick) gets introduced to the glamorous life of Emily Nelson (Lively) after their kids become friends at school. They become fast friends or so it seems as Emily tells Stephanie that she “doesn’t want to be friends with” her after refusing to be photographed.

Things get stranger as Emily goes missing after a mysterious phone call asking for her new acquaintance to do a Simple Favor for her. As new details emerge it also creates more questions. What happened to Emily? Where did she go? Did her husband have something to do with it? Is she alive? That’s for Stephanie to find out.

A Simple Favor, written by Jessica Sharzer based on the novel by Darcey Bell, also stars Andrew Rannells, Linda Cardellini, Jean Smart, and Rupert Friend.

The film will open in theaters on Sep. 14. See the new poster and trailer below.