Vilgax, whose power has been greatly increased, challenges Ben for a battle with the winner named ruler of earth.

After tampering with the Omnitrix, Ben, Gwen and the now mutated Kevin have to rush to hunt a small handful of transformations that escaped, before they cease to exist.

Ben, Gwen and Kevin discovers Vulkanus plans on drilling down to the core of earth.

Ben, Kevin and Gwen are sent to a town where a teenage alien has gone missing during a Spring Break trip to Earth.

An alien named Probity seeks help from Ben to stop the on-going war on her home planet.

Ben and Kevin must travel through space to persuade a judge to reverse his decision to return Ship to the Upgrade who spawned him.

Bounty hunter Sunder is chasing after Ben in order retrieve the Omnitrix. However, once Ben is caught, Sunder inadvertently sends him to the Null Void while attempting to remove the Omnitrix, leaving only Ben's left hand on Earth

A series of earthquakes awakens a HighBreed officer who has been hibernating deep under the earth's surface. He believes the HighBreed have lost the war and activates a fail safe device that is programmed to destroy. Ben must now work together with Gwen and Kevin not only to save Grandpa Max, but also the world from this "giant" problem.

Charmcaster returns and flirts with Kevin in an attempt to steal all of Gwen's powers.

Vilgax returns with a surprise. He needs Ben's help to save his home planet, from Ghostfreak!.

Kevin makes a temporary truce with Darkstar to retrieve an artifact that will return them into their former selves.

Kevin, Gwen and Ben find an alien box that turns into robots.

Ben is asked to deliver Zaw-Veenull, the Luodan ambassador's, crown price Tiffin to Jarrett. However, when the Omnitrix malfunctions, Ben is turned into an Appoplexian named Rath.

While fighting a Techadon robot, Ben, Gwen, and Kevin find themselves transported by the Omnitrix to a planet named Primus. They find out that they are not alone on the planet and Vilgax is there trying to stop the Omnitrix.

Despite being warned, Gwen travels back in time in order to prevent an accident that turned Kevin into a monster. When she returns to the present, Gwen finds that her travel in time caused a ripple of events that led to Hex ruling the world. Now, she must fix the damage she created.

Tetrax visits Ben while he is sick, but shocks Ben when demands a Chromastone from him. Ben's situation gets worse when Vilgax shows up and is after the same thing.

Max sends a message to the plumbers where Ben's attacking Max at a space station. Alan, Pierce & others arrive at t/space station to stop Ben. Pierce suggests working/staying together and no one listens. Later, Helen's attacked/beaten by Echo Echo.

Kevin comes home to find that someone has broken in, and has Ben and Gwen work with him to find out who did it and why. They end up crossing paths with Ragnarok who is looking for a special key, which makes Kevin set out to stop him from getting the key.

Albedo has stolen the Ultimatrix from Azmuth and has used it to kidnap Gwen and Kevin. Ben goes to face Albedo and rescue his friends when he quickly discovers that Albedo has been working in conjunction with Vilgax. Ben is defeated by the pair and gives up the Omnitrix to save himself and his friends.

Ben goes on to Vilgax's ship and tries to stop the invasion of Earth. Ultimately, Azmuth gives Ben the Ultimatrix.