Premise: "Flatline" is the ninth episode of the eighth series of the British science fiction television programme "Doctor Who", written by Jamie Mathieson, and directed by Douglas Mackinnon. The episode stars Peter Capaldi and Jenna Coleman, with Joivan Wade and Christopher Fairbank guest starring. The episode received critical acclaim, with particular praise directed at Coleman's performance.
Hypothesis: One of the guest stars of "Flatline" has the initials C.F.