When a “wandering rogue” guest star steals the show on a time-traveling science fiction program, you’ve got something fun to tune in for. Does it matter that the Big Bad Guy uses a very (very) slow sparkly android and a gaggle of 17th-century townspeople as their footsoldiers, or that the final solution leads to one of the most famous disasters in London’s modern history? Naah. Oh look, a donkey!

The entire TARDIS classroom is back in session, but the history lessons are rather anachronistic in a trip to Heathrow that failed to meet Tegan’s expectations. We love the entertainment factor and witty dialogue, but it’s really Richard Mace who makes this story shine like so many mind-control bracelets.