Max and Phoebe bring Chloe on an undercover mission to Secret Shores so she can experience life as a normal kid. When a new supervillain threat emerges, the trio must stay in town longer than they anticipated.
After Phoebe and Max let Chloe's friends watch a horror movie and eat candy, Jinx and Booch's parents want to meet Chloe's. With Hank and Barb away, Max and Phoebe transform into them to help Chloe. It goes well until the real Hank and Barb show up.
Chloe, Jinx, and Booch are designing a new school mascot, but Max and Phoebe's fighting ruins the project. After Chloe expresses her anger toward her siblings, they realize their twin-fighting impacts Chloe in new ways now that they're guardians.
After a training accident causes a glitch in Chloe's powers, Max and Phoebe look for a cure. After Max thinks he's solved the issue, he allows Chloe to attend a party with friends, but his treatment creates brand new powers Chloe can't control.
Max bets Phoebe she can't turn off being a superhero and go on a normal date. Chloe helps Phoebe do well on the date, but Max tries to sabotage it by crying wolf. Suddenly, a real supervillain emerges and puts Max and Chloe in serious danger.
Cherry visits, and the Thundermans discover she still has her superpowers. Cherry promises to remove them after her girls' day with Phoebe and Chloe, but the powers malfunction and puts the group in danger. Max hosts Jinx, making Colosso jealous.
A new super-fast villain is wreaking havoc in Secret Shores, and Billy is the only hope at tracking her down. After Billy's speed accidentally triggers an avalanche, however, he decides to hang up his cape and retire from being a superhero.
The spin off revolves around Phoebe, Max, and Chloe, who are tasked with investigating a new threat in the town of Secret Shores. While on this mission, they aim to nurture Chloe's superhero abilities.