The Doctor's moods are wide and in a jumble as he settles into his new regeneration. Elsewhere a set of genius twins are kidnapped, whose mathematical computations can manipulate features of the universe. They're immediately put to work by aliens for an as yet unknown end. Written by
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What we need is a cave, some utterly comfortless place where you and I can suffer together.
Why should I be made to suffer?
Because you have been chosen. It shall be your humble privilage to misinter unto my needs. They will be... very simple - but nothing must be allowed to interfer with my period of contemplation.