Plot

A married Hollywood agent receives a mysterious letter for an anonymous sexual encounter and becomes ensnared in a sinister world of lying, murder and infidelity.

A distressed woman calls 911 to report a domestic dispute before confessing to her husband that she recently received a letter inviting her to an anonymous sexual encounter; she accepted the offer and realized she's not happy in her marriage and asks to leave him. The husband murders her with a knife.

Jordan Hines is a smooth talking Hollywood agent who is under constant work stress and five years sober. Although six weeks away from his planned marriage to his fiancée, Caroline, he constantly finds himself distracted by attractive women. He receives a purple envelope with an invitation from an anonymous admirer to a no-strings-attached intimate encounter at a hotel and a form to fill out his sexual interests. He dumps the letter in the trash, but later raids the dumpster and finds it, fills out the invitation and sends it off. After meeting with a potential, high profile Chinese client who later berates him for his agency's practices being obsolete and phony, Jordan receives a second purple envelope with a hotel room keycard. He goes to the hotel room, puts on a blindfold, and has fabulous sex with an anonymous woman who is also blindfolded.

Jordan obsessively investigates the source of the anonymous invitation and the identity of the woman. His new Chinese client had also accepted a similar invitation with another man, and the client's wife shoots and kills him, and the wife of the man he slept with poisons him and herself. Jordan tracks down the delivery person whose bag is filled with anonymous letters in purple envelopes. He investigates one of the addresses and finds the recipient is dead. Jordan's friend PJ theorizes that someone with access to people's social media data, such as recent engagements, websites visited, and liked photos of people they're attracted to, could then have found the addresses of wealthy people who fit the right demographic and sent them letters to connect them for anonymous sex. He suggests it would be inexpensive and very lucrative to set up.

Jordan and his fiancée, having drifted apart as he becomes obsessed with his secret, go to a cabin for a weekend to reconnect. But he continues to rejects her suggestions that there is something going on with him. That night she leads him into passionate sex.

Jordan and his fiancée go to the office of the wedding planner, where Jordan appears to recognize the woman he slept with. She also is there planning a wedding and seems to recognize him at first but claims not to under Jordan's onslaught of embarrassing questions. Jordan resumes his investigation and impersonating a federal agent, investigating the printing press that printed the purple envelopes.

Jordan tracks down and with a hammer attacks the man behind the letters, Johnny, who confesses to sending them based on addresses from The Sony Hacks and further social media scrubbing, in order to match people with their perfect sexual partner. Johnny realizes that Jordan never received the third letter, which would have asked for $5,000 in an anonymous wire transfer in exchange for the identity of the woman he had sex with. He mocks a now-shaken Jordan for being a nobody, initiates his computer program to send out tens of thousands of new letters, and Jordan flees.

In their garage, Caroline catches Jordan burning the evidence of his hotel encounter, where she holds a pair of scissors. Jordan breaks down and confesses not only to infidelity, but drinking, smoking, living a lie and being a fraud. He accepts that Caroline is going to kill him but she forgives him, as she also received the anonymous letters.

Jordan and Caroline escape together and drive towards the border. At a diner Caroline holds her belly and reads news that eight more people have been killed. She explains that they are going to do everything they can to trip the two of them up. The attractive waitress writes her number on the bill she hands to Jordan. (thanks to Wikipedia)