It’s Volcano Day in Pompeii and Peter Capaldi appears as the pater familias of the Cambridge Latin course while Karen Gillan worships freaking lava monsters!!
The Tenth Doctor and Donna arrive in Pompeii the day before Volcano Day.
A local chancer sells the TARDIS behind their backs to, of all people, Peter Capaldi, who’s hosting the city augur later that afternoon.
Seeking out their time machine, our intrepid protagonists stumble upon an alien plot involving lava monsters and stone people.
Somehow Donna manages to piss off the priestesses of the Sibylline oracle — one of whom is played by, of all people, Karen Gillan — and subsequently they try to sacrifice her.
One thing leads to another, and for the second week running the Doctor and Donna Noble find themselves in a cupboard trying to halt a runaway energy converter.