Girl in a Bubble

The TARDIS arrives in Hebe’s flat but it’s not how the Doctor and Mel remember it - and neither is Hebe! In Purity's new timeline, Hebe Harrison lives in a grand penthouse with armed guards and a live-in factotum - Ron! - and if she ever leaves her sanctuary the world will end.

Are these strangers the ones who have been sending her messages? And can this reality be undone without losing Hebe forever?