A dinosaur appears in 1890’s London, and that’s not even the weirdest thing Capaldi must investigate in his debut adventure as the Twelfth Doctor
The grimy gawkers of 1890s London are aghast to see a dinosaur stumbling its way past the Palace of Westminster, but rather than heading into one of the Lords’ bars as customary, it coughs from its throat a curious blue egg, and from this egg hatches the newly regenerated Twelfth Doctor, yet to regather most of his marbles.
The Paternoster Gang once again take the case, but what seems a simple matter of mind-smiting Doc back to health is soon interrupted by the lonely lizard’s apparently spontaneous combustion in the plentifully wet waters of the Thames, and Doc’s disappearance into the night after the one witness with brainpower more potent than a pudding’s.
Clara, meanwhile, can’t fathom why her former colleague is suddenly 20,000 years older. Things look bleak as Madame Vastra must alternate between quick bouts of sleuthing and mentoring on the merits of unclouded vision, Clara must recognise the Doctor for who he really is, and Doc must deal with seditious eyebrows and furious mirrors if the Half-Face Man is to see justice.