If You Give a Time Traveler a Cookie - Loving Who, #4

John and Cici return to St. Louis just in time for Cici to make her eye doctor appointment, but for some odd reason her apartment door seems jammed. The alien time traveler John Smith confesses he might have created a box that produces an endless supply of Thin Mints to assuage Cici's junk food habit. Will they be able to break the door down, stop the inter-dimensional cookie manufacturing, and save the building from collapsing before it's too late?