Alpha is the twelfth episode of Doctor Who Series VII and the first of the two-part finale.
Karlel is in the Stormcage facility when there is a mass breakout. He gets a phone call from the Doctor who picks him up. The TARDIS crew go back to System City where they meet up with Goodwin and ask him about the anomalies.
They go 23 million years into the past through an Anomaly. But when they get back, the System has been destroyed.
An old enemy is returning and the Time Lords will cease to exist.