Besieged by an evil red TARDIS and bounced around from the inside of a living nightmare to ancient China, the Doctor and his friends have had a tough time of late! As Cindy recovers from the... splitting headache she developed on her most recent adventure, Gabby's mysterious block-transfer butterfly powers continue to develop -- and Noobis, the amnesiac offshoot of a former god, continues to grow as his own entity. But the TARDIS team put all that to one side when they visit the distant past of VENUS. What strange civilisation once lurked in its now-poisonous depths? And what connection does it have to the Doctor's own history? And out in the darkness of the vortex, the Time Sentinel lurks. What nefarious plan does it have for the Doctor and his friends?