It's not quite "Gone Girl" but Blake Lively's Emily Nelson gets gone in "A Simple Favor," and the mystery of her disappearance unravels all kinds of secrets.

Lively wiped out her Instagram the other day -- aside from following a bunch of women named Emily Nelson -- and the clever stunt got just the right amount of attention before she shared the first trailer today:

Anna Kendrick plays Stephanie Ward, Emily's best friend and also Emily's fangirl, in awe of her friend's elegance. After Emily goes missing, Stephanie tries to figure out what happened.

Stephanie: "Everybody has a dark side. Some of us are better at hiding it than others."

"A Simple Favor" directed by Paul Feig, was adapted from the novel by Darcey Bell. The mystery thriller costars Henry Golding, Rupert Friend, Jean Smart, Linda Cardellini, Andrew Rannells, and Sarah Baker.

Here's a cool motion poster:

And here are Lively and Kendrick pretending to poison Feig at CinemaCon:

"A Simple Favor" opens in theaters September 14.

Want more stuff like this? Like us on Facebook.