There's this place, somewhere in the universe. An enemy (usually an alien species) attacks it. The Doctor and/or his companions arrive to defend it, sometimes gathering support from what's around them. That's pretty much the plot of every episode of Doctor Who, and now you can create your own mini episodes with the Official Doctor Who Card Game.
The cards feature the Ninth, Tenth, Eleventh, and Twelfth Doctors as defenders, plus Clara, Amy, Rory, Rose, Martha, River Song, and Donna. Each of the Doctors count as "the Doctor" when defending a location, so you can't accidentally double them up on a location and cause a rip in the space-time continuum from your dining room table. And, if you're stuck, you can use a little help from K-9 or a Jammy Dodger to get you out of a ... jam.