Gryben was a temporal enclave to which all unauthorised time capsules travelling within the time vortex were diverted, in order to be catalogued and questioned as to why they were in the vortex. The planet was Gallifreyan territory. According to Coordinator Narvin, a lot of the cases were due to aliens saying either that they were political prisoners or that their planet was on the point of collapsing.
The inhabitants grouped themselves according to which species they were. In the human outpost, Nepenthe, a Free Time agent, lived. (AUDIO: Weapon of Choice)
Robert Knox bought a TARDIS from a Nekkistani on Gryben. (AUDIO: Medicinal Purposes)