sentences:  The script was mainly set in the year 1928 with the Doctor and Romana, aided by Drummond-esque detective "Pug" Farquharson, on the trail of the stolen Mona Lisa, pursuing Scarlioni from Paris to Monte Carlo where his partner, the Baroness Heidi, is using time travel technology to cheat at roulette at the casino to fund Scarlioni's time travel experiments.Other settings included Paris in 1979, Leonardo da Vinci's studio in the year 1508 and prehistoric Earth.At this point, production unit manager John Nathan-Turner had worked out that the production team could afford to film on location in Paris with a stripped-down crew.