 The Doctor picks up <unk> and takes her back to <unk> 's mansion , placing her under medical care of <unk> . He collects the ice fragments from the governess and places them in a <unk> London Underground <unk> tin . He and <unk> travel to <unk> 's lab , where the Doctor notes the Intelligence 's plan to replace humanity with ice creatures and holds up the tin with the necessary DNA . Dr <unk> <unk> the tin and opens it only to find the memory worm , which <unk> on to him . The Doctor states that the Great Intelligence , which has been existing as a mirror of Dr <unk> 's thoughts , will vanish with the <unk> of <unk> 's memories . Instead , the Intelligence reveals that it existed long enough that it can now control <unk> 's body , which it uses to attack <unk> and the Doctor . The influence of the Great Intelligence quickly <unk> , and <unk> falls dead . Outside , a salt @-@ water rain has started , and the Doctor sees that another psychic ability has taken control of the snow from the Great Intelligence : the <unk> family , crying for <unk> . <unk> informs the Doctor upon his return to the <unk> mansion that <unk> only has moments left , and she passes away as the Doctor returns the <unk> key to her . At her funeral , the Doctor reads <unk> 's full name on her tombstone and realises she is the woman he met in " Asylum of the <unk> " who became a <unk> , whom he refers to as " <unk> Girl " . He <unk> announces that a person dying twice is an impossibility and , bidding farewell to his allies for now , the Doctor departs in the <unk> to investigate and find <unk> . The episode concludes in contemporary times , where a young woman resembling <unk> walks through the same graveyard , <unk> by <unk> 's tombstone . 
