The BBC recently revealed the identity of the twelfth Doctor in their long-running SF TV series Doctor Who - veteran Scottish actor Peter Capaldi. But when Capaldi takes over for Matt Smith this coming season, it won't have been his first time on the show. In fact, he appeared in an episode that first aired in 2008 - and it's yours free from the iTunes Store for a limited time.
It was the fourth season (or series, as they say in the U.K.) of the rebooted Doctor Who franchise, when another lovable Scot, David Tennant, had the role of the Doctor (in his 10th incarnation). The Doctor was paired with his irascible companion Donna Noble (actress Catherine Tate). The third episode of the season, The Fires of Pompeii, took the Doctor and Donna back to 79 AD on the eve of the Roman city of Pompeii's destruction from the mighty volcano Mount Vesuvius.
The Doctor and Donna find themselves in the villa of sculptor Lucius Caecilius Iucundus (played by Capaldi) and must unravel a mystery involving a malevolent alien race called the Pyroviles.