Two people who know very little about Harry Potter talk about Harry Potter at length, with a rotating guest expert cringing along.
Mary calls umami the "sixth sense" and Billy gets irrationally angry; guest Rachel provides a lot of tedious information about the Harry Potter series.
Mary discusses the dangers of imagination in the Wizarding World; Billy doubts that owls are faster than the internet; guest Abby leads (and misleads) a long attempt to discover Voldemort's middle name.
Billy tells Mary he wants to see her throw up; Mary is horrified by Billy's hideous description of "thestrals;" guest Madison describes intentionally peeing her pants during the Deathly Hallows Part 2.
Billy flexes his knowledge of such hip terms as "tea" and "stan;" Mary discusses vaping in the Wizarding World; guest Marae extols the coolness of the character Sirius Black.
Mary and Billy discuss churches' relationship with the Harry Potter series; guest Jo declares her hatred for Ron Weasley.
Mary spoils the Phil of the Future finale; Billy does his impression of a barfing cat; guest Amanda is continuously baffled.
Billy and Mary say the C-word; guest Kristina asks about the creatures of the Wizarding World.
Billy and Mary ask: "Do the candy know?" Guest Hannah discusses a Harry Potter class she has taken.
Billy refuses to accept a friendship between a professor and a hat; Mary reveals details of the origin story of her menstruation; guest Meredith proclaims her attraction to Young Ol' What's His Name
Mary and Billy establish the boundaries of their Harry Potter knowledge; guest Hannah introduces some unheard-of character names.