Wait, the Mona Lisa? The Doctor did something with her once. Maybe the reason she wants revenge is she isn’t the original.
For some reason, the Mona Lisa is coming to England, and because Clyde is a good artist, he won a contest allowing his class to see the famous painting first. Rani’s father is more than happy to say so, for once praising Clyde for his work. Granted, Clyde didn’t actually enter a contest. Luke entered the work on Clyde’s behalf.
Also, the kids don’t tell Sarah Jane because Clyde’s painting of three women in the sort of sexy sci-fi poses that of course a teenage boy would draw, are armed with Sontaran weapons, and they figure she wouldn’t approve.
Small problem: upon unveiling, the Mona Lisa shows someone else. That someone else is the curator’s assistant, but he’s so busy fretting over what looks like the theft of the world’s most famous painting to notice. Clyde, Rani, and Luke manage to avoid leaving, and that may be a good thing because one of the guns Clyde included in his painting is also missing.
Because, see, the Mona Lisa is walking around armed with a Sontaran weapon.
By then, Sarah Jane came down to investigate because that sort of theft does pop up in the news and the news likewise even saw fit to mention Clyde won a contest.
Now, it turns out evading an angry portrait, even one armed with alien weapons, isn’t all that hard to do. Mostly because she’s looking for her brother and using the curator to find said brother.
Well, shouldn’t the cops be able to help? There were a lot of them coming by and…oh, there’s all trapped in other paintings.
I am sure Sarah Jane, once she arrives and gets inside, can take care of…oh, she is also trapped in a painting.
Yeah, this might get bad.