In 2011, HBO began a series based on a set of books whose legion of fans had exacting expectations. “Game of Thrones” required condensing a vast narrative, visualizing wonders like dragons’ flight and creating a world that spanned continents.

HBO’s new series “My Brilliant Friend,” based on the wildly popular Neapolitan novels of Elena Ferrante, is a different but no smaller challenge. The story of a febrile and rivalrous friendship between two girls in a working-class Italian neighborhood in the 1950s, it is as intimate as “Game of Thrones” is sweeping.

The first season, which begins Sunday, is set largely in a single cluster of apartments. Its drama, though punctuated by violence, is interior and inwardly focused. It enfolds warring families and shifting alliances, but in a setting where everyone is packed close and prying eyes and whispers are inescapable.

It is a game of courtyards, stairwells and balconies. But as earthbound as it is, “My Brilliant Friend” is no less transporting.