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 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.

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 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.

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 Thundermans are visited by High Tide, the former protector of Secret Shores. But when they explain to him that they are the new superheroes in town, he decides to take back his old role, even if it puts Jinx and Booch in danger.

Max seeks help dealing with a mystery prankster at school from his old principal, who was always the target of his pranks. But Max fails to stop the pranks and quits the mission, prompting Chloe to confess that she was the prankster all along.

Chloe is struggling with her leadership skills, but when a villain attacks her school field trip, Max and Phoebe have to put Chloe in charge while they try to take down the villain and defuse his dangerous astronomical weapon.

Chloe must attend summer school, and Max is assigned to be her teacher. While they will be busy all summer, Phoebe decides to go solo on missions. She meets a new superhero named Captain Perfect, and discovers they make a good crime-fighting team.

Max learns that Phoebe is working with Captain Perfect, and sets out to uncover the secret he is keeping. Chloe's crush invites her to a product launch party at Splat By The Sea, at the same time Jinx and Booch want her to protest outside the party.

Upset that Phoebe has a new partner, Max decides to partner with his friend Gideon. But things backfire when Max tries to turn Gideon into a supersized superhero. Chloe's friends pretend to be wealthy so they can bond with her new crush.

Max agrees to mentor Captain Perfect's younger sister, who is headed down the path of becoming a supervillain. But he has his hands full when she tries to become one of Mastermind's henchmen. Phoebe tries to help BC ask Chloe to the school dance.