The war between the Sontarans and the Rutans has been going on for millennia. And is likely to continue for millennia more. A terrible conflict with no care for consequences or collateral damage. Billions have died with no end in sight.

Its reach can encompass ancient Ireland and a forest world in the far future. Encounters with UNIT and a Doctor no more.

From the outside these battles may seem disconnected. But sometimes there is a common thread. And unpicking that could destroy everything.

When a trip to the planet Taxodon goes wrong the Doctor finds himself with mere hours to prove himself innocent of murdering a Sontaran. As more die, the Doctor and Charley need to uncover the cause and why the Sontarans are even on this planet... if they have time.