When a girl at a local high school sprouts a bunch of extra IQ points, then collapses in the middle of her English lit class, Dyson realizes that something Fae is afoot and asks Bo and Kenzi to join him undercover. Bo gets a bumpy start as a teacher, but Kenzi gets into a brawl with some popular girls. Seeing she'll need a new tactic, she befriends a nerdy chess player, who intimates that the girls might be juicing - taking drugs to improve their intellects, and hence their chances of getting into college.
Lauren chimes in, saying that several ackvim - stupid Fae - attend the school, and the girls' blood streams contain traces of Fae DNA. Kenzi befriends a boy named Earl who tells her about the academic competition he's involved in, and how proud his dad and the Vice Principal are of him these days. He swoops in for a kiss, making Kenzi run away. After complaining to Bo, she heads home, and when Bo returns from a long day of work, she finds Kenzi hard at work being a math genius.
Bo realizes that Kenzi's been afflicted with the same illness that brought the other girls low, and immediately brings her to Lauren's, where the doctor administers a shot to slow down the metabolism of what she now knows to be a virus. Lauren stays in with the now-brilliant Kenzi and tries to hide her life with the Fae from her increasingly suspicious girlfriend while Bo and Dyson head to the school, Bo to meet with the vice principal and Dyson to seek out Earl.
Dyson learns that Earl's dad has been feeding him strange eggs for most meals, and that his grades have gone from disappointing to stellar. Earl says that his dad is meeting with the vice principal, and Dyson brings the boy to the office just in time to see Bo defending herself (quite handily) from a raging father with a hammer. Earl begs for mercy for his father, who spills forth the truth: the ackvim have been second-class Fae citizens for too long, and he only wanted better for his son. The bird that lays the eggs, a species forbidden to handle, is given to Trick to steward, and it seems human teenagers are safe from a paranormal virus for now.
While Lauren has been trying to keep her servitude to The Ash a secret from Nadia, Bo has been trying to put distance between herself and her Dark Fae heavy hitter boyfriend, but when he shows up with a prom fully prepared for her and her alone, her knees get too weak to say no anymore.
Kenzi proves, with the ultimate gesture, that she€™s the best friend a succubus could ever ask for.
Dyson accompanies Bo to investigate the source of all evil only to have the script flipped on him.