Having saved the peaceful Zaarians from an evil alien threat, the Doctor and Yaz sail off to their next adventure. Only this time, Yaz wonders if they're moving on, or running away.

Convincing a grudging Doctor to return to the planet, they are shocked to find the Zaarians in turmoil. What did the Doctor do? Why is the city in ruins? And what's that voice in Yaz's head...?