"I might not have been born on this planet, but it's my home. And I'll be damned if I'm gonna stand back and watch it die around me!" - Aeryn Storm. After the devastating loss of his best friend, Clara Oswald, the Doctor does what he does best. He runs away from his pain. And this time he's run straight into the middle of what could quite literally be described as a 'nightmare scenario', even by his standards. 4.5 billion years in a confession dial was a walk in the park, compared to this. Aeryn Storm isn't human. But she's hiding in plain sight among them. Her special abilities alarm and anger the Doctor at first, but even he sees the benefit in the end. Aeryn also suffers from something the Doctor knows only too well - grief over the loss of a loved on. Can one broken heart mend another? And can the duo find out the identity of the mysterious and deadly killer before it's too late? Or will they become the next victims? (Set Post 'Hell Bent'. Alternate Timeline in which the Doctor was unable to extract Clara from the moment of her death in the Trap Street of London.)