A species of goat-like aliens comes to Earth for a popcorn festival. Ben, Gwen, and Kevin have a big problem when one of the aliens eats meat and turns into a monster.

Ship's owner decides he wants him back and hires some repo men to retrieve him. Ben and Kevin go to court to take care of things legally, leaving Gwen and Julie to face the repo men.

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

Ben, Gwen and Kevin discover that Vulkanus is planning to drill the center of the Earth and drop a bomb into the hole. Destroying the planet.

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

To find and destroy the alien dragon species, the Forever Knights capture Ship to control a starship they built out of alien technology to locate their homeworld and destroy them.

When Ben's parents discover his ability to turn into aliens, they forbid him from using the Omnitrix and later ground him from using it again. Eventually Gwen is grounded too leaving Kevin to stop the DNAliens.

The gang helps the prince of the arachna-chimps regain power

Ben cares for a baby monster and helps locate its parents before the DNAliens find it.

Kevin is beginning to lose all hope that he will someday return to his human self. He then meets a girl who doesn't seem to mind the form he is in. Kevin finds himself under her spell, quite literally, as Charmcaster has come back to exact revenge on Ben and Gwen. Kevin, under Charmcaster's spell, has no choice but to obey his master and destroy Ben and Gwen.

Ben, Kevin and Gwen come across an alien box that can forms into a robotic version of whatever it sees. It power becomes a liability when the Vreedle brothers decide to take the box for themselves.

When Ben stands up to Cash and JT, they soon discover a robotic gauntlet from Kevin's vehicle. With it, Cash decides to get back on Ben, although this time, it's more than just a joke.

Cooper is kidnapped by the DNAliens, who want him to build a mystery arch.

A bounty hunter tries to remove the Omnitrix from Ben.

Gwen discovers that Grandpa Max's badge is able to signal other Plumbers. However, by using it, they meet up with a familiar face, a pyronite.

Freelance young Plumbers mistake Ben and his team as a threat.

Vilgax promises Ghostfreak to spring him out of prison as long as he tells him the secrets of the Omnitrix, but when Ghostfreak betrays him and turns his people into his minions, Vilgax comes to Earth and asks for Ben, Gwen and Kevin's help to get rid of Ghostfreak.

Kevin shatters Ben and Gwen's trust when he steals the Rust Bucket to sell for alien technology on the black market.

Grandpa Max leaves Ben a series of instructions to contact a team of heroes. Things go the wrong direction when they soon find them.

The Forever Knights secure a weapon in hopes of aiding them slay a dragon they have held captive.

The Plumber's Helpers are called upon by Grandpa Max to rescue him from an abandoned space station where he's being attacked by Ben! The team must now find a way to work together as they try to save Max, stop Ben, and keep the space station from crashing to Earth.

The Omnitrix transports Ben, Gwen, and Kevin to a planet called Primus, which turns out to have been created by Azmuth. They must stop Vilgax from stopping the Omnitrix at its source.

Despite being warned by Paradox, Gwen travels back in time to prevent the accident that turned Kevin into a monster from ever happening. Gwen returns to the present only to find that her time traveling caused a series of events that led to Hex ruling the world.

While sick, Ben is visited by old friend Tetrax, who demands that Ben hand over Chromastone.

Kevin returns home to find his house ransacked, so he enlists Ben and Gwen's help to find out who did it and why. They soon cross paths with Ragnarok, a deadly criminal who recently broke free from the Null Void and is in search of a special key. Kevin is intent on stopping Ragnarok from obtaining the special key, especially after he learns the truth about Ragnarok and his father.