Plot summary
In an alternate reality New York City, where advertising is omnipresent, Owen Milgrim is a man suffering from schizophrenia, but hiding his symptoms from his family, including seeing an imaginary brother named Grimsson (who resembles his brother Jed with a moustache) who keeps reminding him that he is on a mission of some kind. His family runs a successful industrial business and are protecting Jed from accusations of sexual misconduct, something Owen plans on defending him from by providing a false alibi. Eventually, Owen is laid off from his job and refuses his father's offer of working with his company and accepting his money.
He hears about Neberdine, a pharmaceutical company, and signs on to test their new drug which can supposedly cure all disorders. While there, he meets the anti-social Annie Landsberg, who Grimsson explains is the agent he needs to see. When he speaks to her, Annie keeps him from getting them both in trouble by "confirming" her association to him, but tells him not to "blow [their] cover". Owen complies as he prepares for the tests.
Credits
Adapted from Wikipedia contributors, Maniac (miniseries). Series, exact episode number and English title matched. Paragraphs formatted; references and illustrations omitted.