The four girls are demoted back to basics after they make a big deal out of saving the prince in the previous season. They are not allowed on any mission, even as a suspicious figure, Carson Lazarus, a criminal mastermind, is released from jail. Soon after, a figure who calls themselves "Retro" causes all technology to malfunction and glitch in Maywood Glen.

The Quail allows the four girls to figure out this case. McKeyla becomes increasingly suspicious of Kyle, but soon dismisses the idea of him being Retro just because he knew she liked fro-yo and was wearing a black hoodie, very much like the one Retro wears. They also suspect Devon D'Marco, a troublemaker, as she spray-paints handcuffs on a picture of a drone on a poster about the upcoming launch. All four girls except Bry, who has to babysit, make ways to get detention on Saturday with Devon. Bry runs a vocal recognition as Cam and Adri confront the troublemaker and McKeyla looks through her bag. Devon is proven to be innocent, just using the school's 3D printer to make skulls for her nana's birthday.

When a new point of evidence involving HAVOC points to Carson Lazarus, Adrienne and Bryden comb through her trash looking for clues.

Bryden analyzes Retro's voice, which gives the girls a new idea about his or her identity; and they need to use their wiles when a blackout threatens to delay their investigation.

Retro sets a trap for the girls, which causes the Quail to advise them to leave town.

When the girls learn about the Quail and McKeyla's super-secret plan to infilerate HAVOC, they enlist some new friends to help out with the mission.

The Falcon tasks the girls with investigating a string of robberies, and EDM band EliTe returns to Maywood Glen to perform a surprise concert

While Bry and Cam do some sleuthing at rehearsal, Adri and Ember create a gummy bear tracking device to help McKeyla find Maddy.

When a nightmare about Maddy leaves her reeling, McKeyla comes clean to the Falcon. Bry and Cam kill it at auditions and zero in on a new suspect.

Ember's itching potions sends Grady to the nurse's office, where Adri and McKeyla question him. Bry discovers a mysterious clue in EliTe's music.

McKeyla and Cam question Eli at his grandmother's house and follow him to the docks, where they learn about a diabolical plan.

The girls arrive at the Maywood Glen art opening to search for Vex, but they have no idea what the elusive mastermind looks like.

The girls visit NOV8's amazing headquarters, where the Quail gives them a new mission involving an old friend. But something strange is afoot.

The girls try to stop an intruder from stealing a prototype from Space Inc. When things go awry, McKeyla begins to doubt her sleuthing skills.

McKeyla, Bryden and Adrienne discover a dark side to the nanotechnology prototype. Cam and Ember make a brainy new friend at Destination Mars Camp.

McKeyla homes in on a surprising new suspect: Camryn's dad! Meanwhile, Ember and Cam wonder if fellow camper Gordon is up to something.

Devon uses art to help Bryden and Adrienne work through their differences. McKeyla has a difficult talk with Kyle about their relationship.

The girls finally learn who's responsible for stealing the prototype. But is it too late to stop the evil mastermind's plot?