In Brakebills University, Quentin and Julia take a test in which their magical skills are tested. Quentin passes the test, but Julia fails to her dismay, whereupon she seeks help from Pete to reenter the test.
Quentin, Alice, Penny, and Kady are in over their heads for causing the Beast's attack on Brakebills. Meanwhile, Julia doesn't stop herself from exploring the world of magic and takes another test to join the hedge witches.
As Kady steals an important book and give it to Marina, Quentin is forced to go to Marina's hedge witches hideout, where he is surprised to see Julia. Penny discovers he has the ability to travel between worlds.
A demon bug is the only way to save Quentin from his hallucinations that he woke up with in a mental hospital. Quentin causes Julia to be dismissed from the hedge witches group after she seeks help from Dean Fogg.
Everyone has got no chance to steel their selves for Welter's Tournament, as Quentin discovers his father has cancer, while Julia tries to join another hedge witches. As for Alice, she returns to Brakebills, while they discover Penny has traveled to Fillory.
Third year students came up with a set of challenges to first year students, during which Quentin mend fences with Penny, to whom Kady confesses she was taking advantage of him in seizing things from Brakebills. Julia gets to know Kady's mother while trying to deceive Marina into stealing her spells.
In South Antarctica, the students are taught at the hands of Professor Mayakovsky, who hatches a plan to relate Quentin and Alice into a relationship, and tells Kady about her mother's death, and that she is no longer a student in Brakebills. Eliot and Margo get ready for their vacation in Ibiza.
After Mike attacks Penny and stabs him with a cursed blade, he pretends he didn't do anything and forgot all about it, whereupon Eliza tries to deal with him, but he kills her. Meanwhile, Julia is introduced to religious magic by the counselor Richard in rehabilitation.
Quentin, Alice, Eliot and Penny head to Plover estate in England, after Penny discovers that the book which he destroyed was about Fillory, in which the author Jane Chatwin stated that there is a magic button in Plover's mansion that leads to Fillory.
While Penny is stuck in Neitherlands and is unable to get back to Earth, Quentin and Alice try to seek help from Penny's relative to travel between worlds and save him. Having spent 6 hours in Neitherlands, Penny learns how to defeat the Beast.
For them to do away with the Beast, Quentin, Alice, Penny, Eliot and Margo get ready with their dark spells and train on hedge witches' battle magic, which leaves them having lost sense of place, time or identity.
After a long night of drunkenness, Quentin, Alice, Penny, Eliot, and Margo travel to Neitherlands, while a force drives Quentin back to Earth to find out that Eliza is Jane Chatwin, and cooperates with Julia to go back in time to unravel the truth about Fillory and the Beast.
Traveling back to 1942, Quentin and Julia meet Watcherwoman, Jane Chatwin in the past, who is able to send them to the rest of the students. It turns out the Beast is Jane's brother, Martin Chatwin, by whom Julia and Quentin are attacked in Fillory and the rest of the team face their destinies.