It's chaos aboard Presley Station, as the corrupted Shan'tee - conceptual beings from a different order of reality - prey on the human colonists, while on the gas giant below, vast storms conjure up winds of horrifying speed -- that threaten to tear the Station apart! Caught in the middle of the chaos: the Doctor and Gabby!
Can the Doctor find the counter-melody that brings peace back to the Station? And can the ever-humming Gabby keep herself from singing - to stop her mind being invaded by a sentient song?! Meanwhile, back on Earth, Cindy makes up her mind... And in deep space, an old face comes calling...!