A Stutter in Time (Doctor Who Fanfiction)

Clara Oswald has been travelling in her TARDIS with Ashildr, but ultimately, she know knows Gallifrey is calling. All paths lead to the Extraction Chamber, between one heartbeat and her last - which could be coming sooner than she thought.
The Quantum Shades are aware that their contract has been broached and despite the gimmick with the Neural Block, time isn't healing. They're closing in on her.
When Clara receives a distress signal, she follows it to the planet of Harth-To. Unbeknown to Clara, the Doctor has also received a distress call leading him to the same planet. Who sent the signal? And why are the Shadow Proclamation terrorising the planet?