The Doctor and Romana II find themselves in Paris, investigating a fracture in time, when they find themselves face to face with not one but six copies of the Mona Lisa. All of which appear to be authentic. Oh, and the original's still hanging in the Louvre. Hmmm... The six Mona Lisas (Monas Lisa? Monae Lisae?) are all the property of one Count Scarlioni, who (as if all the Monas weren't enough) has a scanner for alien life, cleverly disguised as a bracelet on his wife's wrist. Now the Doctor's interest is thoroughly piqued.