Darkness has reconciled with Light. Entropy has made peace with Eternity to produce a limitless unidirectional Time. It has been three weeks since Dairine talked the Lone Power out of their aeons-long campaign of destruction. And she's getting kind of bored again.
Look, school just doesn't seem very interesting when you've got the whole universe to learn from. And since the speed of light is less of a "limit" and more of a "place where the math gets interesting", she can be back before she left. So why not go exploring?
She sets up the parameters of her jump carefully, entering criteria into Spot (her laptop-slash-wizarding-manual) until she has a clear specification of what she wants. It should be somewhere with a breathable atmosphere and reasonable gravity. It should be somewhere with a bunch of nonhumans, because her level of disorientation in that alien airport last month was really embarrassing and she wants to do better this time. But it should also be somewhere with at least one other human, so there's someone with context on both here and there to talk to about any miscommunications. It should be somewhere really far away and really weird. And most importantly, it should be somewhere she can help people.
The program finishes loading. Dairine double-checks her extradimensional pockets to make sure she has all her useful items, including a large supply of food and appropriate dishes and silverware this time, she is not coming back from two adventures in a row covered in mustard. And then she pulls aside the twenty-seven-dimensional curtain that separates every Here from every There, and steps.