Books in the Doctor Who: The Lost Stories series in order

This story sees the role of popular companion, Sarah Jane Smith, originally played on TV by Elisabeth Sladen, taken up for the first time one audio by her daughter, Sadie Miller.

The Doctor, Romana and K9 find themselves at the centre of a most unusual trial when an intergalactic corporation wants to bulldoze planet Earth for a development project. If The Doctor can Earth contains intelligent life, the whole world will be saved. But with a fortune at stake, it was never going to be that simple.

During one of Nyssa's experiments, the TARDIS's temporal scanner picks up a message: 'Idra'. Just one word, but enough to draw the Doctor to the Archipelago of Sirius. There, the Autarch is about to announce a new crusade. A mighty war against Seth, Prince of the Dark...

With the TARDIS working perfectly, the Doctor and Peri decide to take a holiday. But where? A long-forgotten piece of equipment in the TARDIS storage locker sends them to the peaceful and idyllic continent of Tranquela - home of the Doctor's old friend Ravlos.