The final episode. Ray, Louis, and Hunter try to free Alex and her parents from the Plant which is lined with bombs thanks to Danielle Atron. Meanwhile Dave works with Gino and the FDA to stop the chemical plant from releasing GC-161.

After four years of keeping her powers hidden, Alex's secret world is falling apart. As the Plant prepares for the release of GC-161 to the public, her dad loses his job, and Louis discovers her secret powers, and is captured by the Plant.

Alex saves a woman's life but can't tell the authorities that she double-morphed the woman to the hospital. The mystery heightens Danielle Atron's suspicions. As Annie prepares for college, a bittersweet realization comes over the sisters who share so much.

Alex carelessly uses her powers and ruins Annie's interview with MIT. She runs away, thinking everyone would be better off without her.

Alex and George discover that gifts and decorations aren't as important as the Christmas spirit, while Dave's gift to Vince is a chimp that runs amok in the plant.

Junior camp counselor is a new role for Alex, and one for which she's not well-suited. She and Kelly get lost in the woods, are chased by a bear and learn the importance of two words: friendship and rescue. George remembers his own camp experiences with mixed emotions.

The plant closes in when Alex's journal, detailing her powers, ends up in the wrong hands.

Alex, Raymond, Nicole and Robyn notice a new neighbor moving in. It turns out to be Louis Driscoll, a cool-looking kid with a wisecracking attitude. The more Raymond likes him, the more Alex doesn't.

Aunt Ashley is everything Barbara isn't: fancy, outrageous, irresponsible, crazy. Alex's wild go-cart ride with her aunt forces Barbara to get tough with both of them. Alex's school work suffers while her spirits soar.

At career day at the plant, Alex is taped using her powers and she, Ray and Annie have to sneak back and get the tape.

Alex, Raymond, and Nicole are facing their first junior high school midterm in history class. Libby, the most popular girl in school, has her own ideas about surviving the midterm and studying isn't one of them. Libby decides to pull the fire alarm right before the exam.

In anger, Alex jeopardizes her mom's job. Later, she tries to make it up to her.

Alex steals a test to help Nicole, who is cracking under the pressure of the exam. At the plant, George discovers that GC-161 has the capability to alter human genetic structure.

Annie aces her English Advanced Placement exam, allowing her to attend a writing class taught by a renowned author. Inspired by her sister's achievement, Alex sets her mind to engage in extracurricular activities in the hope that one will bring her some recognition. She discovers an unusual talent for cow milking and wins the Dairy Decathlon. Meanwhile, Annie experiences her first academic failure.

Alex asks her sister for help with a class science project, but ends up using her power to impress the teacher. This gets her into trouble when the teacher believes that the project was done by Annie, not Alex. Meanwhile, Dave and Vince disguise themselves as janitors in an attempt to find Alex.

Annie's science project has been chosen as a finalist for the big science fair to be held at the Paradise Valley Chemical Plant. The whole Mack family is looking forward to spending Saturday at the science fair rooting Annie on, except Alex. Not only is she sick of witnessing Annie's triumphs, but the chemical plant is the worst place for her to be. It's crawling with plant spies who are constantly on the look out for "the kid."

Alex and Ray have a falling-out and Alex is afraid Ray will disclose her secret to the plant.

Ray captures Alex's powers on video and wants to enter the tape in the Atron JH Video Award contest--but Danielle and Vince are the judges!

Alex gets a job with Louis at his dad's distributing company so she can buy her own car.

Alex becomes friends with the new boy in school, Hunter, who may know something about the GC-161 project.

On her way home from school Alex Mack is practically hit by a truck. The truck is carrying a top-secret chemical and spills it on Alex. Alex learns later that she has magical powers and shares this secret with her sister, Annie, and best friend, Raymond.

The morning before Halloween, Alex and Ray come across Paradise Valley's haunted house while delivering newspapers. The next day, Louis convinces Alex and Ray to check out the old house. When Alex takes a closer look, she's sucked in by a mysterious light and comes face-to-face with the woman of the house.

Alex inspires Robyn to face the dreaded ""Rooney Runabout"" and pass P.E.

While Louis is innocently taking a photo, he catches Alex's zapper-gone-wild on film. He's sure he's captured some kind of UFO that will make his footage famous. Meanwhile, Alex helps George overcome his fear of bowling.

When Hunter finds out about the GC-161 accident he starts searching for the GC-161 kid in order to expose the plant and uncover the truth about his father's disappearance.