This is four episodes set in ancient Rome, unsurprisingly. As per the norm, a light-hearted holiday turns into a fight for their lives, as Barbara and Ian get captured and made into slaves. By astonishing luck, the Doctor and new girl Vicki just happen to be heading to Rome (well, all roads lead there – it’s the name of part 2) and both groups manage to get themselves out of trouble again without actually running into each other.
Seriously, Barbara becomes a servant to the Caesar where the Doctor is pretending to be his new musician, Ian rescues her without the Doctor or Vicki seeing either of them, and they all escape separately! The Doctor even gets into some fisticuffs this time, although his half of the adventure is rather more light-hearted on the whole. I lost count of the number of times he laughed hysterically in this story. Every other line seemed filled with giggles.
Oh, then he gives Nero the idea to burn down Rome.
Overall, a weirdly mixed tone, more jovial than normal, but a fun romp.