From ANN:

After the last world war (2100-2104), the earth has become a desert place to live. Even more : the scarce resources left are destroyed by the ZPT system to clean the earth for the return of the Mars colonists. Louis (the only boy in the gang), Liza, Mill and Wooty, together with the Android Mamet, have accidentally found each other with the same target. They search for the source engine of the ZPT to destroy it and thus stop the useless destruction of the remaining cities and people on earth. In their journey, they have to fight mechanical devices, revolutionary armies and Martians to get to the core of the ZPT engine.