Penny Dreadful‘s fifth episode of the season, “Closer Than Sisters,” airs tonight, and in it we’ll be finding out exactly what the relationship was between Vanessa and Mina.

Last week on ‘Penny Dreadful’

Malcolm and his team started treatment for the creature they’re keeping in their basement: A blood transfusion. They think it worked, but in the end, of course, it did not. The creature’s master comes and sets him free from his chains and while he goes to attack Malcolm, he realizes Vanessa is not there, and tells the master, who then flees through the window. In the altercation the creature dies.

Meanwhile, Ethan takes Brona to the theater to show her a good time and it turns out that Dorian and Vanessa are there as well. During intermission they all meet in the lobby, and it turns into quite an awkward situation (if you remember that Dorian paid Brona to have sex with her on camera) that leads to Brona leaving, upset. As she gets sick on the streets and passes out, Ethan and Dorian bond over some illegal gambling games and end up going back to Dorian’s place, where they end up having sex after the ingestion of some homemade absinthe.

This week, we’ll find out more about how Mina disappeared.

We know that Malcolm and his team are on the lookout for his daughter, Mina, and that’s why they’re hunting for the creature’s master: they believe he’s taken her. So now we’re going to see more about the past with Vanessa and Mina. The synopsis reads:

Vanessa recalls her past and the events that ultimately lead to Mina’s disappearance.

And in case you missed it last week, check out the trailer for tonight’s episode that shows us more of their history: