Martha's Clone

Martha Jones was cloned by Sontaran Commander Skorr.

Before the Clone looked like Martha
Two members of U.N.I.T found a massive tank in a room. When it opened, they saw a strange creature. That was a clone, ready to look like one of the U.N.I.T soilders. When the hypnotised U.N.I.T soilders took Martha to Skorr, Skorr decided to use Martha as the image of the clone. She could do nothing but watch as the Sontaran made the Clone look like her. Not even a single feature about the clone was different.

Stopping U.N.I.T launching the rockets
The first thing that Martha's Clone was ordered to do was to stop U.N.I.T launching the rockets. She got a device that could control the U.N.I.T computer and just before they were going to launch the rockets she switched the computer off. Mace and the rest of U.N.I.T didn't suspect a thing. Except the Doctor. But she didn't know this. After she did this again, U.N.I.T changed their plans and used the Valiant to stop the gas that the Clone and the Sontarans had made.

The Gas
Every car that had ATMOS in it was in trouble. The Clone and the Sontarans made gas surround London using the ATMOS systems. And, as I have said, U.N.I.T used the Valiant to stop the gas.

The Death
When the Doctor found the real Martha, the Clone grabbed a gun and threatend to shoot him. He reveals that he knew that she was a clone all of the time because she "smelled funny". Then he woke up the real Martha by taking the things off Martha that made her sleep. She needed to sleep to keep the Clone's memories alive. When Martha woke up, the Clone started to die. Before she died, the Clone told them the Sontaran's plan was Clone feed.