Michael is an immortal demon whose life's purpose has been to torture humans in the afterlife. Recently, he came up with a new method of torturing humans. However, whilst experiencing this experimental torture, the humans realised their errors on Earth, and began trying to learn morality. Part of this realisation also involved the humans discovering a major flaw in Michael's process - one that could get him fired from human torturing, and therefore sentenced to eternal damnation. Michael befriended these humans and was taught moral philosophy with them, and now vehemently opposes the torture of humans. As a result, he helps them enter the "Good Place" - the eternal positive afterlife designed specifically for human enjoyment.

Laurie is a young man with a large inheritance living in Massachusetts. He is in love with Jo, his best friend, an independent young woman who is pursuing a career in writing. He is close with her family and her 3 sisters. In 1869, Laurie proposes to Jo. She declines, citing her ambitions, desire to never get married, and platonic love for Laurie. Heartbroken, he leaves for Europe, where he grows close with and ultimately marries Jo's younger sister, Amy. Meanwhile, Jo moves to New York, successfully begins to publish her writing, and eventually accepts a proposal from a colleague.

Dating in Materialists is highly transactional and shaped by status, wealth, appearance, and social expectations. The style of dating represented in the film centres around most eligible young people paying substantial amounts of money for 'matchmaking' services (either in person or online), with the goal of finding a partner being their material or aesthetic value rather than deep emotional connection.

When ghosts start appearing in 1970s London, industrialisation almost completely halts—the only innovation that continues is in ghost-removal technology. Only children can perceive ghosts, and interactions with ghosts are usually deadly. Agencies employ children to enter haunted spaces and remove hauntings. Ghost removal may include physical combat and problem-solving.

By 2015, two models of agencies exist:

Corporate agencies such as the Fittes Agency are for-profit, adult-run agencies that uphold strict standards and operate with top-of-the-range innovative equipment. The adult supervisors prioritise high-risk and high-reward projects that they oversee. The Fittes Agency was established by Marissa Fittes, who detected the first ghosts in London and became the first ghost-removing operative. The agency is run by her descendants. 

Independent agencies such as Lockwood & Co are co-operatives run entirely by teenage agents. They charge smaller fees to clients, meaning their projects are smaller, but their resources are limited. Their smaller size means agents are close friends and prioritise team dynamics. One of Lockwood & Co’s agents, George, has a hobby of researching the history of hauntings in London.

Camp Half-Blood is a summer camp for the children of Greek gods (known as demigods). Demigods attract attention from monsters and other evils, proportionate to the power of their godly parent - up to a near-guarantee of dying for the children of Zeus, Hades, and Poseidon. Demigods have skill proficiencies or magic that aligns with their parent's domain. At Camp Half-Blood, these skills are harnessed, and children undergo simulated combat, weapons training, and other intensive activities.