Sarah ends her relationship with Zack. Zack discovers a sword in a stone, and pulls it out. Then Merlin appears, who is usually ""an old guy with the blue hat"", is now in the form of a teenager, and reveals that he was trapped in the stone and continued to grow younger instead of older. No one can see Merlin, except for Zack, and no one else could pull out the sword out of the stone except for Zack. Zack decides to ask for getting back together with Sarah, so Merlin grants him his wish if he completes his quest of bravery while Spencer is thrown all around while trying to obtain some evidence of the 2000-year-old wizard.

When Zack and his friends go on a camping trip, Zack's father decides to join them to give them tips. Zack, trying to get away from his father wanders into the woods with Spence and Cam. But they were suddenly zapped into another world, and they must try to find a way out.

As the Season Finale, Zack's records were sent out the window when he participated in a fight with Vernon, and Zack lost his entire memory. Zack's friends must retrieve the Zack Files and tell him all of the most important Zack Files to give Zack a chance to retain all his memory. Clips of previous episodes in Season One and Season Two were viewed in attempt to get Zack to become himself again, and once he saw his record files that Vernon had retrieved to announce to Zack that he was one of Vernon's minions, his memory was restored.

Zack must take part in a Shakespeare play - Romeo and Juliet in order to pass English class, and he was assigned to act as the role of Romeo.

When Daniel Greenburg accidentally buys Girl Power deodorant for Zack while shopping, and Zack uses it, he becomes a girl! Now, Vernon is flirting with Zack, while Gwen starts plucking his eyebrows. And even worse for Zack, Cam is going on a date with Sarah. Zack decides to find out how to change back into a boy after he gets some secret information from Gwen and Sarah.

Gone Zack becomes invisible when he drinks invisible ink.

Zack's fear of growing up causes him to regress back to childhood when he discovers that he is going to have a Bar Mitzva Celebration at his church. Zack actually transformed back to when 7 years old, and he started acting like a child while Spencer try to figure out how to get the teenage Zack back. Zack's Bar Mitzva was getting nearer while Zack stayed in school and fooled around, causing trouble for Spence and Cam. Spence needed to make Zack feel more grown up and ready to accept the responsibilities of a boy who is becoming a man.

But I'm Too Young to be my Dad When Zack's future son, Mack, travel back through time to get help from his father Zack realized how difficult it is to be a parent.

The Library Of No Return Zack finally gets around to returning an extremely overdue library book (Alice in Wonderland) and is confronted by a furious Queen of Hearts, White Rabbit and Mad Hatter who put Zack on trial for his carelessness. Cam and Spencer are there to help him by becoming his lawyers and proving to the Queen of Hearts that Zack had not ripped out pages from the book, and it was Vernon who did it.

Crypt Seeker Computer game dream girl, Tara Bond, comes to life and quickly becomes Zack's worst nightmare. In exchange, Spence is trapped inside the computer with Bond's sidekick. Cam and Zack must find a way to throw her back into the game.

Exit, Stage Fright Zack gets a bad case of stage fright, which of course, causes his pants to dissolve.

The Bottom Line Zack finds out that he can accurately predict the future using his new glasses. When he holds something, words would begin to form that explained to him what would happen in the future with that object. Cam started to buy and buy chocolate bars because there will be a shortage of chocolate in the future while Zack became a star when everything found out he had such power.

Zack wanted to stay and work on his project with Spencer and Cam, so he tried to trick Floyd, by turning the clock handles back to a certain time but they were transported into the past where they meet a boy. When they returned to their own time, the boy from the past came with them. So now, Zack, Spencer, and Cam has to return the kid back to his time before it's too late.

You Don't Say Zack and his Dad pay a visit to Henry Gold's Magic Shop where Zack picks up a guide to Vaudeville ventriloquism. With a little practice, Zack learns to throw his voice. He started to have some fun during class, and humiliate Vernon during his presentation, etc... Soon, Zack's voice was becoming more weak and Zack was starting to lose his voice. Suddenly, his voice was released from Zack and it starts telling everyone his secrets. Secrets about his friends, and Zack must retrieve his voice before all his thoughts about his friends are out.

Dinner With Grandpa Grandpa Maurice, who had passed away, drops by the Greenburg's for dinner. Zack was the only one who could see this ghost. Dan invited Jennifer, his mother - Leah and Zack's friend Sarah dropped by.

Deja Vudoo It was at Gwen's birthday party where Zack had his first date, and Spencer was videotaping the event to see if anything strange happens. Zack finds out that he could rewind time and end his disastrous day, but everytime was a disaster.

Anchovy of Doom When he was working on his science project about Human Apportion, Zack decided to take a break and eat some pizza, but before he ate, he zapped Gwen, Dickie, Tad, Todd, and Vernon into a terrarium and all of those 5 became only 8 centimetres tall.

Sparkin' Zack can create sparks and romance between people after visiting the Science Centre

Photo Double Zack accidentally gets stuck in his Photo ID card when an old roll of film steals his image, leaving his body in a zombie state. Zack needed to get out because he had a date with Rita, but it didn't work so the zombie Zack had to go, with the help of Cam. Spencer looked for a photographer and finds a model, to explain about the situation, and how to resolve it.

The Talented Mr. Talisman Zack enlists the aid of an ancient charm doll to protect his accident-prone father. Soon, Zack finds out that Zack's father was fired from his job because that was what Zack wanted - Daniel not to be ever injured again.

This Is Your Conscience Calling Zack and his conscience have a falling out when Zack abuses his ATM privileges. When he found out that his bank account was set with lots of money, he starts spending hundreds of dollars on items on the Shopping Channel. He soon realized that it was a glitch and he must pay back the thousands of dollars he spent.

The Switch Zack and Charles (Vernon's Butler) switch bodies when they go through a revolving door at the same time. Zack had a rough time doing everything for Vernon while Charles helped Zack's father a lot by preparing dinner, cleaning everything in the house, etc...

It's A Jungle In There Zack's neighbour's apartment turns into a jungle. His friends try to find a way for Zack to escape.

It's a Wonderful School It's election-time at Horace Hyde-White School for Boys and Headmaster Killerby unveils his latest acquisition - an early 20th century voting machine. Everyone's worst nightmare is realized when the voting machine misfires, transforming Horace Hyde-White into the Vernon Manteuffel School.

A Place Of My Own Zack finds out it is very hard to live on his own, when he magically receives an apartment.