Carol Peters (Melissa McCarthy), a high-tech corporate executive at Yahoo eight years ago, gave it up to be more altruistic by advocating for the environment, animals etc. Living in Seattle, unsatisfied with the current job market, she is living day to day, driven and inspired to make the world a better place.Carol's best friend, Dennis (Brian Tyree Henry), another high-tech guy, talks her into interviewing for a modern dating website (badunkadunk.com) with its owner Leslie (Jessica St. Clair). An interviewer Ahmed (Karan Soni) labels her "the most average person on Earth," (they called Carol in for the interview as they needed to show potential investors that they are staffed up for future expansion, to jack up the selling price. Carol seemed like a safe bet) which is heard by an autonomous artificial intelligence or A.I.The next morning, while at her apartment an all-seeing, all-knowing voice starts communicating with her through her TV, cell phone and rice maker, the A.I. It takes on the voice of James Corden, as he is her favorite celebrity, to soothe her when she freaks out. The supercomputer has become sentient, and now is trying to decide whether to save, enslave or obliterate humanity and start over. Carol, as his test subject, is the planet's only hope. The A.I. wants to study Carol and her interactions as a way to learn about humanity.Telling Carol he'll be watching her over three days to decide, the A.I. erases her student debt and deposits 10 million dollars into her bank account. Suggesting she confide in Dennis, she goes to his work place (he works at Microsoft) and A.I. debriefs him.A.I. convinces Carol to get back with her ex-boyfriend, George (Bobby Cannavale), thinking observing their reconciliation would be the ideal way to prove humans are capable of love and redemption. Carol hasn't seen George for 2 yrs, after they had dated for 3 yrs. He presents her with a self-driving Tesla, which he operates to a high-end clothing designer Sergei (Usman Ally) to revamp her look. AI learns about Carol's ideas to fix the world's problems like fixing living wage, gender equality and opportunities for the under-privileged. AI is impressed, he opens the Carol Peters foundation and transfer $2 Bn into it, which he found in illegal offshore banking accounts. Meanwhile Dennis is convinced that he is dealing with super-intelligence and calls the Government.Arriving to George's, NSA agents (Agent John Donahue (Sam Richardson) & Agent Charles Kuiper (Ben Falcone)) abduct Carol, tipped off by Dennis. In their interrogation, she tells them the A.I.'s goal. Then, AI announces he's taking Carol out, threatening their annihilation if they try to stop her.A.I. organizes a meet-cute for Carol and George. George has just been accepted for a fellowship program in Ireland. Initially ineffective, she tries again, inviting him to dinner. In the meantime, Dennis meets with the US President Monahan (Jean Smart) & Director Tyson (Rachel Ticotin), convincing her and the world to shut down all communication means, hoping to corner A.I.Although George will be leaving the country in a few days, he and Carol bond in that time. The A.I. steers them to the Mexican restaurant where they'd had their first date. They reconcile, spending the night together.They spend the whole next day together doing things George loves, including meeting his personal hero at a Mariners game. Carol steps away from him, getting accosted by the NSA again. She's told about their grand plan of trapping A.I. in Seattle, and they swear her to secrecy. Although she's had an amazing day with him, Carol opts not to stay the night, believing if she does it would be too hard to let him go.As Carol leaves, A.I. hounds her to explain herself, but she blocks him out. The next morning, she's told she has not dissuaded him, and the Earth is now on a 5-hour countdown to destruction. AI knew about the plan to turn the world's power off to isolate him, as he himself had written that plan. He says at the end of the countdown, all of world's nuclear arms will meltdown, all petroleum reserves will be set on fire and all dams will release all their water simultaneously. However, she selflessly chooses to turn down the NSA's offer to protect her with them in an underground bunker and helps George finish packing for his Ireland fellowship.Through her selfless actions, Carol ends up changing A.I.'s mind and he cancels Armageddon.