What happens to Quentin at the end of the first book?

Quentin, the main character in The Magicians by Lev Grossman, is fascinated with a fantasy world called Fillory. One day, he receives a letter stating his acceptance to a university of magic called Brakebills. Upon entering this university, he discovers that he finds magic studies just as tiresome and bland as studying any other major outside of the magical realm. Throughout the story, Quentin and his classmates abuse hallucinogenic drugs, as they are widely available in the world of magic. He discovers that the land of Fillory is real and travels to this land. However, it is no longer the land he once read about, as it features the Beast and political upheaval.
Near the end of the book, Quentin is in a coma, from which he awakens many months later. He discovers that he was a pawn in Jane’s plot to kill the Beast and becomes severely depressed. The book closes with Quentin taking a regular job in the non-magic world, where he seems to have a deflated affect and essentially wastes his day away on video games. Then, one day, his friends from Brakebills pay him a visit at his office. Quentin decides to accept their invitation to return with them to Fillory, where they will reign as kings and queens.