Acting on a tip from Strax , the Doctor visits the Great Intelligence Institute posing as Sherlock Holmes . He confronts Dr. Simeon and find a large glass globe in Simeon 's office that contains psychic snow . The Doctor speaks to the Great Intelligence , the entity that has been speaking to Dr. Simeon since he was a boy . He learns that the Great Intelligence has been controlling the snowmen and has taken interest in Latimer 's pond . The Doctor visits the pond and deduces that the Great Intelligence is using the old governess ' body as a DNA blueprint to form an ice creature that will retain its form and not melt . While Clara is putting the children to bed , the frozen body of the governess breaks into the house . The Doctor fights her off and is joined by Vastra , Jenny and Strax . Dr. Simeon arrives with more snowmen and tells them he wants the governess ' ice body . The Doctor flees with Clara to the roof of the mansion and then to the TARDIS hovering overhead . They are pursued by the ice governess , whom the Doctor traps under a layer of frozen ice crystals . Inside the TARDIS the Doctor gives Clara a TARDIS key , but the ice governess arrives and pulls Clara down off the cloud .