Garth's prankster cousin Rodney pays a visit. Whilst staying he manages to not only annoy everyone, but also turn into a half-man half-spider (Spiderboy).

Angry that Toby and Nikki are together, Elizabeth sticks Toby in a time loop, so he repeats the same day over and over again.

Elizabeth creates a freaky machine to be her new assistant, but it becomes consumed with the idea that he must protect Eliizabeth and soon her safety is in danger.

When Elizabeth goes to any extent to get information out of Russ, Jack finally gets evidence proving they are geniuses. Will he get away with it?

After Verity does an experiment by a lake, the experiment goes wrong and Verity is slowly turning into an amphibious monster.

Elizabeth's tricks accidentally enable Sasha with extraordinary abilities to communicate with animals Dr Doolittle style.

Because no one trusts Jack,he makes sure that Toby and his friends are all distracted so that he can take a peek in Toby's shed. But will he end up regretting this?

Elizabeth is sacked as director of the school's centenary celebration, and vows to ruin the celebration by destabilizing the set.

Toby and his friends discover a koala, whilst Garth's stupidity lands the enlarger ray in Jack's hands. By a series of events the koala enlarges and causes havoc across the school in a mist created by Toby? Will Toby and Elizabeth's secret come out? Will Jack act on his suspicions?

Elizabeth reveals a T-rex to a press conference at the school, but the T-rex rampages through the school. Toby creates a giant doll to fight the T-rex, and the doll wins. Toby zaps himself and Elizabth with the MFE, removing their genius. However, Elizabeth still has the genius key in the pocket.

Toby attempts to use the genius key to turn off Elizabeth's genius. Toby and Elizabeth meet secretly in the gym, and just as Toby prepares to cancel Elizabeth's genius, Mr Tesslar walks in seeing Toby with the stolen MFE.

Sasha and Russ accidentally swap bodies after messing around with one Toby's inventions.They learn to appreciate each other's good qualities.

Still love-struck, Jack talks Elizabeth into making Toby normal again. She agrees and goes off to perform it. While she is out of the way, Jack turns himself into a genius.

Toby has to meet Nikki's parents. But Jack and Elizabeth have teamed up to make it a disaster.

Elizabeth gets revenge on a famous Hollywood actress who starts attending their school by playing a childish prank.

Toby creates a remote control that allows him to win an arcade game, but the game goes berserk.

Toby's nanna is sent back in time through a wormhole generator, and a younger version of Toby's nanna comes through the wormhole, destroying the generator.

Russ is convinced he is a loser, so Toby helps by building a time machine so Russ can see his heroic ancestors. But it all goes wrong and Russ is time-swapped with a man from prehistoric times. Will Toby be able to save Russ?

Toby uses his flying machine to help Russ, but doesn't know Jack is watching. Meanwhile, a dog-lover offers to donate money to the school. How will Jack try to blackmail Toby for the genius key this time?

Toby creates an organic growth accelerant for Dina, after Elizabeth makes Dina's hair fall out. The organic growth accelerant results in Dina growing a beard.

Elizabeth teams up with Garth to put some muscle into her plans.

Toby finds the correct sequence, called the genius key. He accidentally turns Russ into a genius.

Toby creates a robot Dina, so she can be on her date with Sean and work her shift at the same time.

Elizabeth, in her basement lab uses too much power and Mr Tesslar tries to track it down, but she sets up Toby and Russ to keep the location of the basement lab safe.

Toby modifies the MFE machine to scan for Bianca in a rocky landscape. He finds a rock that reacts strangly with the MFE.

Toby throws a beach party for Bianca's birthday. Elizabeth is not invited, and makes a storm at the beach using electromagnetic waves on the clouds.

Toby tries to prove he is a genius by creating an anti-gravity machine, and fixing it to the school's ride on lawnmower. Elizabeth sabotages Toby's plans to make sure no one finds out they are both geniuses.

Elizabeth and Dina both run for Class Rep. Elizabeth uses anti-friction spray on her competition, putting Dina in a dangerous position.

Elizabeth sets up a secret lab in the school's basement, and orders Garth to shrink objects from the storeroom; but Dina discovers him. Panicking, he shrinks Dina.

Toby decides to create a visual memory for Russ who holds the missing element of how he and Elizabeth became geniuses.