The home of the 3D9C universe, starting with 3 Doctors, 9 Companions, What Could Possibly Go Wrong? followed by 4 Doctors, 12 Companions, What Could Possibly Go Wrong? and concluded with 5 Time Lords, 13 Companions, Can Anything Else Go Wrong? all of which are the same long story revolving around the multiverse collapsing and leaving unstable interdimensional rifts. When the Eleventh Doctor and Clara Oswald's TARDIS passes through one of these rifts, the rupture in spacetime causes the Ninth and Tenth Doctors, along with all their companions (Rose, Jack, Mickey, Martha, Donna, Amy, Rory and River) to get pulled into the console room, forced to balance domesticity and their personal lives with adventures through time and space. Later on joined by Oswin Oswald, Adam Mitchell, and Jenny (the Doctor's daughter), reunited with her father after 207 years. A second universe splitting after The Name of the Doctor also emerges, creating two different Claras and two different Twelfth Doctors.

Also part of the universe are four spin-off fics: The Lost Echosodes, Jenny Who?, Spooky Hollow and Retrograde.

The Lost Echosodes stars Oswin and Clara venturing trapped in a hallucinated dream-world together, set between Chapter 236 and 237 of 3D9C, meeting a new Echo in a new place every chapter.

Jenny Who? is a prequel story about everything that happened to Jenny after The Doctor's Daughter and before Chapter 38 in the 200 years when she was on her own (the only one which is standalone and makes sense without the canon of the others.)

Spooky Hollow is about what happens when Esther Drummond - ex-CIA, ex-Torchwood, ex-dead Lightning Girl - has to house share with Sally Sparrow - supernatural nut, insomniac and conspiracy theorist extraordinaire. (Previously called Spook Watch)

Retrograde is the same chronology as the main 3D9C trilogy but set fifty years onwards and follows Clara and a female, parallel-universe Twelfth Doctor (who predates the end of the Moffat era), who are married and living together in Brighton in 2064 working as teachers, but still fighting off alien threats at every opportunity.