Ah, standard link system. Rather brilliant, actually. Sounds similar to a reality rip I know well - place in Norway called Bad Wolf Bay that opens into a different world.
And is that what it is! Stupid of me not to realise. Someone very important to me is in this world, when she oughtn't be. Another person I know was a child when I knew her, and now she's in her twenties when time hasn't progressed that much.