Congratulations Max and Phoebe Thunderman. You are both finalists for a slot on the Legendary Z-Force... as a team! Good luck.
The Z-Force is an elite team of superheroes on The Thundermans. It is run by the Hero League and comprises of the best superheroes in the league. These are the kind of superheroes that other superheroes call when they need help. The chances of joining the Z-Force are usually very low and getting into it is usually a big honor.
The Z-Force usually communicates to superheroes by projecting a hologram of its logo as seen in Thundermans: Banished!.
In Thundermans: Banished!, there was a new slot opening in the Z-Force for the first time in 9 years. The Z-Force sent out invitations to some of the best superheroes for a chance to fill the slot. They chose Phoebe Thunderman as one of the finalists for defeating one of the most powerful villains, Dark Mayhem in Thundermans: Secret Revealed. They said would observe her over the coming months to determine if she's qualified for the slot.
Phoebe got so excited for the spot that she didn't want to continue training Max anymore because she was afraid he would make a rookie mistake under her watch. So, Max made a fake Z-Force communication beam, saying that he was chosen for the same slot too. This increased competition among the Thunder Twins, leading to the destruction of Splatburger. Phoebe later figured out that Max had programmed his watch to project the Z-Force signal. President Kickbutt withdrew the twins' names from the Z-Force for messing up and the Thundermans were banished from Hiddenville.
However, after Max and Phoebe risked losing everything including their powers to save Hiddenville from Candi Falconman, the Z-Force announced that both Phoebe and Max Thunderman are now both finalists to join the potential open slot, as a team.
The plot of this episode revolves around Phoebe and Max's Z-Force training. Max and Phoebe have been given money for Z-Force training equipment but Max uses the money to build a team headquarters for him and Phoebe. Also, Max has a Z-Force poster in lair.
The twins are submitting their special skills to Z-Force. Phoebe has already submitted all of her skills. Max wants to enter gadgets development as his special skill and so he creates a Crimecaster gadget which can predict future crimes. After doubting his skills, it turns out that the gadget actually works and therefore the twins agree to enter Max's gadget development skills for Z-Force.
According to President Kickbutt, the Z-Force was fighting a giant, radioactive worm in the center of the Earth.
Z-Force sends a representative to interview Phoebe and Max as part of the Z-Force recruitment process. Unfortunately, Phoebe has injured her neck and legs while trying to help Cherry. So, the Thunder Twins enlist Cherry to pretend to be Phoebe for the Z-Force interview. They dress Cherry in Phoebe's Thunder Suit, and teach her all the questions they expect to be asked by Z-Force. The interviewer from Z-Force arrives and is easily fooled into believing that Cherry is Phoebe. He complains keeps complaining about how he didn't make it into the Z-Force. He later takes the "twins" on a mission, hoping to make a name for himself in the Z-Force. Max and Phoebe pass the Z-Force interview, advancing to the next stage.
Max and Phoebe get a special TV interview by Anderson Super, a popular Metroburg TV host for their Z-Force progress. After learning abour the upcoming Supe Awards, Max is concerned that a stink bomb he set as a prank back when he was evil could jeopardize their chances of getting into Z-Force. Both him and Phoebe are so concerned about losing their opportunity at the Z-Force that Phoebe ends up absorbing Dark Mayhem's powers from the power-sapping orb in order to be able to stop it. She successfully stops the stink bomb and secures the chance at the Z-Force. But unfortunately, the powers turn her evil.