Mija (Ahn) lives with her grandfather on a farm in South Korea, where she has spent the last 10 years bonding with a super-pig named Okja. When the multinational Mirando Corporation, led by Lucy Mirando (Swinton), comes along to collect Okja and take her to New York City for testing, Mija is devastated at the thought of losing her beloved pet. With the help of some members of an animal rights group, Mija sets out to save Okja from the hidden cruelty of the Mirando Corporation.
Laura (Ricci) moves with her 7-year-old son to a peaceful and remote lakeside house to escape her abusive ex-husband. Things look beautiful as they try to settle in, but Laura is on edge, constantly worried her ex-husband will find a way back into their lives. To add insult to injury, things get more intense when her son catches a glimpse of what appears to be a monster lurking out in the lake. With their hopes of starting a new life dashed, Laura starts questioning her sanity as her perception of safety begins to crumble away.
When tech genius Finley Hart (Hopkins) dies, five remote agents from different parts of the world are contacted by an A.I. that instructs them to reactivate the initiative, a machine that could enable time travel. Hart's machine, painted as humanity's greatest achievement, may not be all that it seems, and the strangers must work together to decide whether the consequences of ignoring Hart's final wishes are worse than those should they do as instructed.