In the season premiere we start where we left off, with Helen Magnus following Adam Worth back in time. Adam intends to use the knowledge he learned from Hallow Earth to save his daughter from a rare blood disorder that has no cure. The problem is he is changing history and this time travel could have dangerous effects on the future, but he doesnt care.
Upon arriving in Victorian era london, Helen chases Adam through the streets until she is knocked out from falling debris. The police arnt sure what to make of her. She is odd, dressed in clothing they have never seen, and carrying items they have never heard of. Dr. Watson shows up to the jail to come get Helen and when they open the cell he nearly blurts out that he doesnt know her, yet he simply asks Helen to come along with him.
Back at the Sanctuary, he knows something isnt right. Her hair is black, she is wearing strange clothing and she is carrying technology and weapons unlike anything of the time. As an inventor and genius detective, Watson soon understands that while she is Helen Magnus, she is not of this time. Helen warns him not to ask any questions to avoid damage to the future by having too much knowledge. He knows better then to challenge here on that.
Watson continues to explain that simply talking with him and being here will have an effect on the future and Helen fears that he will not discover the truth of “Jack the Ripper” as he did before. At first Druid is blamed for the killings but in fact an abnormal named Jack is responsible for the deaths and with a little help from future Helen, Watson is able to discover this as he did before.
Helen continues to seek out future Adam Worth, when Adam of the past comes to her and Watson for help. In the past he came to them to try and find a cure, but events have been altered and Adam is seeking Watsons help to find his now missing Daughter. Future Adam has taken her and events have been altered. When Helen finally catches up, Adams daughter has been healed and Helen worries about the repercussions.
Helen chases Adam down, she cannot allow him to continue changing the past and in an interesting twist, Adam misses a blaster shot at Helen and hits the terrace above her and Adams daughter appears in the alley just as the terrace falls and kills her. despite his efforts she died anyways. In a fit of anger he draws his gun on Helen before she kills him. Just as this happens, the past Helen and Watson show up to find her body and past Adam shows up upset and angry at Helen and Watson for not helping him to save her.
In the end, the future has repeated itself in a way, but what changes might we see in the future as a result of interference in the past. Will Watsons history change? Will Druids? Helen decides to go into hiding for a 100 or so years until present day returns and she can go back to the Sanctuary right when she left. But what will have changed now that Adam has altered history?