‘We’re in Pompeii and it’s volcano day.’ Unlike Rose, Mickey and Martha, Donna has already passed the audition before her first trip: this is more about emphasising why the Doctor needs a companion, and why Donna in particular, playing back into the point that, ‘Sometimes I need someone.’

From Donna’s perspective it’s all about making her understand the awesome responsibility the Doctor faces; the deaths of 20,000 people – or entire planets – sitting on his conscience. It does this by replaying the end of The Parting of the Ways (and, by implication there and confirmed in The Day of the Doctor, the last day of the Time War), with the Doctor confronted by a big lever, a terrible choice and the consequences: ‘I make it happen.’ Interestingly, Donna choosing to share the guilt, helping the Doctor to push that lever, is essentially what his successors plan to do for the War Doctor towards the end of The Day of the Doctor.

So, this one is steeped in the new series’ lore – an impression reinforced by the appearance of Peter Capaldi and Karen Gillan in the cast; Lucius’ prophesying the return of Rose and Donna’s encounter with the Time Beetle, and the mysterious loss of Pyrovillia. But it also calls back to The Romans, with mention of the Doctor’s part in the Great Fire of Rome, and the pay-off to The Aztecs: ‘You failed to save a civilisation, but at least you helped one man’. It also finds space for some fantastic monsters (both the impressive Pyroviles and the petrified priestess), the very funny Sooth-off as Lucius and Evelina compete to come up with the most impressive insights. The end result may not be the greatest episode of the series but is perhaps the most quintessential. The Pyramids of Mars of the modern show.

Next Time: Planet of the Ood