We watch "The Pilot" (Series 10, Episode 1) where the Doctor coasts along as a chilly college professor until new companion Bill Potts tries to soft reboot him into giving a damn again. Whilst said thaw is occurring, a shoddily reconstructed Nardole is falling to pieces, Bill meets the woman of her dreams who just wants to make Bill wet (unfortunately in a non-consensual way), and the Doctor finds the drive to travel again... as long as the mysterious vault he and Nardole are guarding remains sealed. To paraphrase Brad Pitt’s character in "Seven," What’s in the vault Doctor?