Written by Robert Khan and Tom Salinsky, Doctor Who - The Early Adventures: The Ravelli Conspiracy is out today starring Maureen O'Brien and Peter Purves in a new story set in the First Doctor's TV era:

When the TARDIS lands in a house in Florence, Italy in 1514, it isn't long before the guards of Guiliano de Medici arrest Steven and Vicki. To rescue them, the Doctor has to employ the help of the house's owner - one Niccolo Machiavelli. But can he be completely trusted?

Guiliano confesses to his brother Pope Leo X that he has angered the wealthy family of Ravelli and believes the newcomers may be part of an assassination plot. But when the Doctor arrives an already tricky situation starts to spiral out of control.

As the city rings with plot and counter-plot, betrayal and lies abound. The Doctor and his friends must use all their ingenuity if they're not to be swept away by history.

This conspiracy is about to get complicated...

Doctor Who - The Early Adventures: The Ravelli Conspiracy is available from today on Download or on CD (which instantly unlocks a digital version). If you're using the free Big Finish app for Android or iOS devices, then you can be listening within minutes to the latest adventure for the Doctor, Vicki and Steven!

You can subscribe to all four stories of the third series of Doctor Who - Early Adventures, with the first two series available as money-saving bundles. This third run of tales concludes next month with Doctor Who - The Sontarans, as the First Doctor encounters the popular clone-race foe... For the first time!