The Doctor is taken "out of time" by the Time Lords and made to face an inquiry into his meddling in the affairs of others, overseen by the Inquisitor. The prosecutor, the Valeyard, soon has the proceedings upgraded to a trial for the Doctor's life. Evidence takes the form of recordings of the Doctor's recent adventures, beginning with his visit to the mysterious world of Ravalox and an encounter with Andromedan space pirates...

The Doctor has an appointment with the Immortal, while Peri finds herself caught up with Glitz and the Tribe of the Free. Meanwhile, Merdeen begins to question all he believes.

The Doctor escapes to rejoin Peri on the surface but shortly becomes the prisoner of a surface-dwelling tribe called The Free. Ravalox isn't Ravalox after all, but before the Doctor can learn much more an irresistible agent from UK Habitat comes to fetch him back.

All those on Ravolox are in exponentially greater peril than anyone can comprehend. If anything in the entire universe is to survive, it may come down to the Doctor arguing against machine logic over the value of life.