Once again, the steering of the TARDIS proves a bit unreliable as the Mandragora Helix lures it to Earth and to the realm of "Duke Giuliano" (Gareth Armstrong) who has only just recently inherited his title and thereby earned the enmity of "Count Federico" (Jon Laurimore). Now we know that when out time travellers arrive, that is always a precursor to a mystery and this time, the "Doctor" (Tom Baker) and "Sarah Jane" (Elisabeth Sladen) find themselves embroiled in the mysticism of the menacing "Brethren of Demnos". When "Sarah Jane" falls prey to this cult of black-clad people under the increasingly malevolent influence of "Mandragora" and his lackey "Hieronymous", the "Doctor" must try to rescue her from his evil clutches before she does for him! This four part series allows a reliable supporting cast - including Tim Piggott-Smith - to dress up as characters from the 15th century Romagna and has a solid story that, though not especially original, continues to entertain whilst incorporating a little Leonardo da Vinci into some new world thinking on both the religious and scientific fronts. The visual effects are quite effective from time to time and the dense forestry scenario provides well for plenty of bows, arrows and superstition!