It is the sequel to Pike's #1 New York Times best-selling debut, Wings,[3] which introduced readers to Laurel Sewell, a faerie sent among humans to guard the gateway to Avalon.

Jamison welcomes her back to Avalon and tells her that the gates were made by King Oberon (at the cost of his life) and that Winter faeries are the only ones who can open them.

She is introduced to professor Yeardley, who gives her a stack of books to read, and told that Katya, another Fall faerie, has agreed to tutor her.

Laurel wants to see Avalon, so Tamani takes her to where the Summer faeries live.

Laurel asks to see where the Spring faeries live and Tamani takes her to his mother's house.

Katya hands Laurel over to Yeardley, who says he'll be teaching her defensive herbology instead of the typical rudimentary potions.

Tamani says things at the gate have been quiet—suspiciously so—which prompts Laurel to ask if he ever gets tired of being a Spring faerie, given their low social status.

Jamison arrives to escort Laurel to the gate and tells her that Yeardley is very pleased by her progress.

He catches her up on everything that's happened whilst she was in Avalon; her mother's new apothecary store has opened (bought with the money from Jamison's diamond) and Chelsea is dating another student named Ryan.

It goes well until Laurel, forgetting that she is a plant and humans are animals, gives incorrect recommendations to a customer at the apothecary store, which sparks an argument between her and her mother about how they don't talk anymore.

They enjoy themselves, but Laurel spots a troll and abruptly realises that she is out very late past sundown; the perfect time for Barnes to attack her.

They are caught, with one of the trolls ripping out several of Laurel's petals, but are saved by a woman called Klea Wilson.

She offers them both bodyguards, but Laurel refuses, worrying they might discover the sentries guarding her or the gate.

David is absent from school the next morning, and Laurel panics until he shows up and suggests they skip their afternoon classes, and takes her for a picnic.

He accuses Laurel of not wanting him in her human life and she demands he take her back home.

David, angry that Laurel lied, and suspicious of what exists between her and Tamani, says he doesn't want to see her for a while.

She begs David to come help her save Chelsea and he agrees, driving to the specified meeting point—a lighthouse—as Laurel mixes potions in the passenger seat.

Booklist gave Spells a starred review and wrote, "Mixing a little bit of Harry Potter and a lot of Twilight ... Pike has hit on a winning combination.

Yet it is her own graceful take on life inside Avalon that adds a shimmering patina sure to enthrall readers.

"[8] Salt Lake City Weekly found that "...Pike's tale is more than another derivative hero-quest narrative.

While telling a fanciful story about faeries and trolls, she cleverly interweaves an effective teen coming-of-age yarn".