The Doctor and Sarah Jane Smith's desperate struggle to survive while uncovering and opposing the supernatural threat posed by the Mandragora Helix cult within San Martino

The Doctor slips from his pursuers’ sight, abandoning a stolen horse before vaulting over a balustrade and descending steep medieval stairs into San Martino’s maze of alleys. Past a building …

Count Federico makes his move while Giuliano distracts Sarah with a grand scientific idea about the Earth’s shape. Federico’s armed men cut off their escape, blocking the paths as he …