The Great Intelligence finds the Doctor’s grave, and that’s no good for anybody.
Season Three, Episode Nine.
The Cybermen try to assimilate the Doctor. Big mistake.
Season Three, Episode Six
The Doctor disappears in Victorian-era London, leading his friends in that time to investigate his connection to mysterious red-skinned corpses.
Sisko is taken to the Mirror Universe to perform a mission only he could pull off.
An accident in space causes damage to the TARDIS, time zombies, and Clare learning stuff.
Season Two, Episode Five.