Timeline 1 Edit
When she started to work at the Horizon Gallery, Penelope had to watch over the Paradox chamber. She made sure that no one looked at it for to long. After some time Penelope heard a voice in her head telling her that she was going to be the most famous woman on the planet. It turned out that this was the voice of the paradox.
Then the Eleventh Doctor appeared at the gallery and told her that something bad was going to happen. A claw touched Penelope's shoulder. It was a skeleton creature from a nightmare. Its mouth opened as if it was going to say something. However, the Doctor stopped the monster, who just said one word: "Stop". After it the creature disappeared.
Later the creature reappeared and killed Geoffrin and Mr Silver, the manager of the gallery. Then the chamber with the Paradox was closed for several years. People could only view it from the outside.
When the chamber was reopened many people were attacked and Penelope turned blind. The Paradox still talked to Penelope in her head. It told her how to build a machine that should prevent her from dying. Penelope built the machine.
She later realised that by using the machine she became the creature who attacked all the people. The creature was an older self of her who wanted to warn her not to work at the gallery. That is why the creature had said "stop" when Penelope first met it. The creature also wanted to take revenge on all the people who wronged her, including Mr Silver and Geoffrin.
Later the creature became the Paradox, which was going to kill the whole planet.
When Penelope realised that the Paradox was her older self she sacrificed herself before becoming the creature and the Paradox. Therefore, in the new timeline the Paradox never existed and Penelope was guarding an empty chamber. (AUDIO: The Art of Death)
Timeline 2 Edit
Mr Silver hired Penelope to guard an empty chamber. The Eleventh Doctor, Amy Pond and Rory Williams visited the Horizon Gallery and the chamber. The Doctor suggested to Penelope to fill the chamber with her own paintings. Penelope liked his suggestion. (AUDIO: The Art of Death)