Every now and again, the BBC managed to draft in some heavyweights onto it's flagship "Dr. Who" series and this one is amongst the best. We get a clue of what's to come from the explosive start before the "Doctor" (Tom Baker) and "Romana" (Lalla Ward), who looks like she's just escaped from "St. Trinian's", arrive for a sojourn in Paris. Sitting in a café they experience some sort of time loop, then on a trip to see La Giaconda at the Louvre - one of the best museums in the galaxy, don't you know - they both begin to become suspicious that not only is the painting's safety in question, but the ...