Season 4 - Episode Guide

Season 4 begins with Chase, Adam, Bree and Leo discovering that a confidante has secretly formed an evil rebellion to exact revenge for his father's death by killing Davenport. Meanwhile, Leo informs everyone that he is not "one of them" but brags about living with Adam, Bree and Chase in their high-tech quarters.

Adam, Bree and Chase sneak a group of bionic students off the island but accidentally leave Spin and Bob behind. They then scramble to retrieve them before Davenport finds out.

Everyone becomes convinced a new threat has emerged when a series of suspicious events occur overnight.

Douglas' long-lost dog shows up on the island. Chase becomes severely allergic to it, while Adam instantly bonds with the pooch.

Leo promotes himself as the fourth member of the team and creates more mission alerts than the team can handle.

Adam and Chase each lead their student groups against one another in a series of simulated exercises that evaluate student and mentor performance.

When Leo is injured during a mission, Tasha rushes to the academy to take care of him. She quickly realizes the danger he puts himself in on missions.

Douglas and Chase work together to reanimate an extinct species of sea spider. The spider escapes and puts the entire academy in jeopardy.

Bree and Chase discover that a female bionic student has a commando app like Chase. After she starts terrorizing the academy, they activate Spike to subdue her.

Davenport's top scientist Dr. Ryan arrives at the academy to test his latest advance in space technology. Chase is immediately threatened by his young surfer dude demeanor and their rivalry heats up when Chase is forced to work as Dr. Ryan's assistant.

Douglas reveals that a former colleague is a movie director & wants to make a movie based on Adam, Bree and Chase. However, when she shows up to the academy with her actor Troy West (played by Leo Howard) for research, her evil agenda begins to unfold.

An amnesic S-1 arrives at the Island, scared, lost, and vulnerable. Chase and Douglas discover from her that Krane implanted the bionic students with a deadly virus. Chase, Douglas and Leo desperately try to find a solution before time runs out. Meanwhile, Adam and Bree try to make their last hours comfortable. Bree wants to have a party and Adam wants to set the world record for most balloons in a room.

Douglas develops a new piece of technology replicating Chase's bionic intelligence and gives it to some of the other academy students, including Bob. Meanwhile, Perry takes over the island, and instantly abuses her powers and makes everyone's lives miserable, especially Leo and Bree.

Davenport gives Eddy, the smart home system, a synthetic human body, and he quickly becomes a model employee working alongside Terry. Meanwhile, Chase gets an offer to go to Washington to work for the President.

When Terry Perry brings back a skull from a neighboring island, everyone is convinced that it's cursed when strange things start happening to those who come into contact with it. Meanwhile, Adam tries to introduce Bob to the art of scaring people.

When the president awards Adam, Bree and Chase for their heroics, Leo feels left out and forms his own team. When Leo discovers he and one of his teammates have joint bionic abilities, he pushes her to the limit which causes her to lose her eyesight. Racked with guilt, he moves back to Mission Creek but is forced to regain his courage when his family is put in extreme danger.

When Tasha gets everyone except Perry tickets to the big college football game, Perry creates mayhem. Upon arriving at the game, Perry and Davenport go head-to-head in the ultimate tailgate challenge judged by former NFL athlete Willie McGinest.

Everyone is shocked when Douglas introduces a fourth bionic sibling named Daniel who's been living a normal life with an adopted family.

Donald takes everyone for a visit to "Davenportia," the first human space colony located on a remote planet in another galaxy.

The academy students suddenly vanish after receiving an operating system upgrade. The team initially blames a glitch, but realize the kids are pawns in a much bigger master plan. The Lab Rats put their lives at risk when they face off against the vanished students' captors - a nefarious duo they recognize from their past.