Summary: There are unearthly phantoms at large and no escape for the people trapped beneath the lake.
The research facility beneath the lake is different, even exciting once they realise something weird is going on. There are strange phantoms stalking the corridors and each death adds another to their ranks.
Excitement soon turns to fear though, and Clara almost wishes she hadn’t been so eager for another adventure. Be careful what you wish for because it might not seem quite as appealing when you get it.
The Doctor is a ghost now, although he’s still alive and trying to fix things in the past. Clara can only pray his plan works before they run out of time.