In this collection's first episode, we learn that Albedo has switched places with Ben for a few days now and seems to have everyone convinced he's their friend and compatriot. That is, until Ben, who has been stuck in Albedo's cell, finally escapes and is able to convince the Plumbers who he really is. Meanwhile, it's obvious that Ben's duplicate is biding his time for something and it isn't long before the doppelganger succeeds at his plan. Not only does Albedo get his fake Omnitrix working again, but he regains his normal Galvan form and even retains the ability to turn into ultimate forms of the aliens - a feature Ben no longer has with his newest Omnitrix.
The last two episodes in the Albedo storyline has the shapeshifter Galvan working with Khyber in a plan to take Ben out once and for all, as well as letting Albedo get his vengeance on Azmuth.
Ben gets captured by the evil duo and finds himself on a world where he is prey for Khyber's new pet, a feline alien that has Ditto's duplication ability. As Ben (in Ditto form) runs in different directions, so does the new pet. Meanwhile Max and Rook start looking for any sign of Ben and find more than they are looking for.
Before the Duel of the Duplicates story wraps up, Gwen and Kevin join in the fight and Albedo succeeds in removing Azmuth's brain with the intent of absorbing all of the alien's genius. Ben also gets a couple of new aliens added to his repertoire and Albedo shows us a few ultimate forms we haven't seen before. Just to make things more complicated, Ben and the group now have to deal with a stupefied Azmuth, all the while trying to return the Omnitrix's creator back to his former self.
Ben 10 Omniverse: Duel of the Duplicates also comes with two bonus, non-Albedo related, episodes. One has Dr. Animo talking and plotting to himself while in his cell. It seems the crazed villain is about to retry an old plan that almost worked once. This episode actually takes place primarily during the 11 year-old Ben storyline. In it, Ben, Gwen and Max are headed to the rebuilt Mt. Rushmore Plumbers Headquarters, but find themselves being attacked by Animo and one of his creations (a two-headed giraffe with laser beams). When the doctor is able to use some modified bugs in order to take over the base, Ben and the rest of the Plumbers have to infiltrate and shut down their own security.
In the last episode on this disc, Ben's biggest fan, Jimmy Jones, returns. While watching the latest news coverage of one of Ben's jobs, Jimmy notices some strange new aliens lurking in the background. Jimmy then decides to head to Undertown on his own in order to see what he can find out. Of course, he ends up biting off more than he can chew when he uncovers one of Ben's former foes, long thought to be completely out of the picture.
Ben 10 Omniverse: Duel of the Duplicates is a good collection of episodes. The Albedo episodes make a good storyline but aren't enough for a full disc, and the added one-off stories do a decent job of rounding out the collection. All deal in one way or another with Ben's past, and mix newer characters with classic ones in some amusing ways. All together, any Ben 10 fan should check out these episodes.
