The evil Highbreed aliens have captured Ben Tennyson's cousin, Gwen, and imprisoned her in a large fortress in an alternate dimension. Join Ben 10 as he unleashes the Omnitrix Aliens on the Highbreed prison fortress to rescue Gwen and stop their evil plan for galaxy domination! Using the special powers of the Omnitrix and the aliens’ Echo Echo, Big Chill, Spidermonkey, Chromastone, Humongousaur and Swampfire, Ben 10 must break down the fortress walls and defences and destroy it before it is too late for Gwen and the galaxy!