Victorian London harbours many secrets: alien visitors, strange phenomena and unearthly powers.

But a trio of investigators stands ready to delve into such mysteries – the Great Detective, Madame Vastra, her resourceful spouse, Jenny Flint, and their loyal valet, Strax.

If an impossible puzzle needs solving, or a grave injustice needs righting, help can be found on Paternoster Row.

But even heroes can never escape their past…