Ep 15. The Next Doctor

The Doctor arrives in Victorian-era London on Christmas Eve, only to discover that another man is also calling himself "The Doctor" and is fighting off evil Cybermen alongside a companion named Rosita. The man claims to have no memory of his life before a year ago and believes himself to be a Time Lord, but the actual Doctor suspects there may be something more mundane going on. As the two Doctors team up to stop the Cybermen's plans, they also begin to unravel the mystery of the imposter Doctor's true identity. Along the way, they explore themes of memory, loss, and the legacy of the Time Lords.