Ben 10 episode 1 season 1

 The first episode of "Ben 10" is titled "And Then There Were 10" and it originally aired on December 27, 2005. Here's a brief summary of the episode:

In "And Then There Were 10," we are introduced to the main character, Ben Tennyson, a 10-year-old boy on a summer road trip with his cousin Gwen and their Grandpa Max. While exploring a mysterious meteor crash site, Ben discovers a strange watch-like device called the Omnitrix. The Omnitrix attaches itself to Ben's wrist, granting him the ability to transform into various alien creatures.

As Ben begins experimenting with his newfound powers, he comes across a villainous alien named Vilgax, who wants to obtain the Omnitrix for his own sinister purposes. Ben quickly realizes the responsibility that comes with his new abilities and decides to use them to protect the world.

Throughout the episode, Ben transforms into different alien forms, including Heatblast, Four Arms, and Grey Matter, as he battles Vilgax and his robotic drones. With the help of his cousin Gwen, who possesses magical abilities, and his Grandpa Max, an experienced former plumber, Ben manages to defeat Vilgax and save the day.

"And Then There Were 10" sets the stage for the rest of the series, as Ben continues his adventures with the Omnitrix, facing various threats and encountering new allies and enemies along the way.