After a quick brain racking I came up with some ideas.
An Irish family is forced to leave the Island due to a murder
which was commited in self defense against a prominent member of
the community (perhaps the father protecting the daughter
from the advances of the attempted rape by the mayor’s son).
They arrive in London, where the father gets a job as a dock hand
for a shipping company owned by a wealthy London family. This London
family’s head is a high ranking member of the Free mason’s. The father
overhears a little too much information about these secret dealings and is forced to make a decision, either he become a henchman for the Family
or be deported back to Ireland to face the mercy of the authorities there. The man agrees due to the fact that his family would not be able to survive on their own. He puts the man in charge of a shop which is a front that is used to carry out certain business between members of the masons.
I also thought about the possibility of a love affair between the Irish man’s daughter and a son of the head of the aristocratic family, but not sure how that would tie in yet.
Just a real brief and basic idea to get the juices flowing. I just need an SL that shows how the shop has come into the hands of the current owner.