This is the story of Ben, a typical kid who becomes very atypical after he discovers the Omnitrix, a mysterious alien weapon with the power to transform the wearer into ten different alien species!

 

CAUTION PLOT SPOILERS!

Ben 10 Season 4 revolves around Ben's last adventures as summer vacation ends. Revolving around the leader of the Forever Knights organization, Forever King, and his plans to deal with the Tennyson's. He gathers many of Ben's enemies to serve as members of his group, the "Negative 10" to both battle the Tennyson's and steal a powerful energy from the Plumber base at Mount Rushmore. Ben eventually defeats the Forever King, destroying the Mount Rushmore faces in the process! The series' final episode shows a possible take on Ben's return to normal life following the end of his summer vacation, and ends with the reveal of his secret powers to his father and the general public, after a final climactic battle with Vilgax.