The plot was that the Evil Twins and the Ants were taking over the world and Crash had to travel to different planets in different dimensions using the Psychetron. Most of the enemies set to appear can be seen in Crash Twinsanity's concept art (the Goat King, rock bees, etc). The known worlds that were set to appear are: a fish-people inhabited world, a planet known as Gaudi, and a place called the "Hanging City", where the rich people live in the hanging part and the poor live in the slums below.
The fish people can be seen in Crash Twinsanity's concept art, along with a worker from the Hanging City Slums. A designer of the game released this information. There is also concept art for the game showing Crash in a space suit but no more information has been found about it. Further concept art reveals that many past characters such as Komodo Joe, Ripper Roo, and Koala Kong were set to return. Crash was also going to have to undertake quests to gain the trust of the inhabitants of each world.
The storyline of the game was changed to what became Crash Twinsanity because the original plot was too similar to the game Ratchet and Clank, in the sense that the antagonists were taking the best parts of other planets to make their own.