Zoe Marconi just became a whole lot more important to the plot of Nine Perfect Strangers. Up until this point, the youngest member of the Marconi family has been a background player, much like poor Ben and Jessica. But in the fifth episode of the season, Masha singled her out as "the key" — the key to what remains to be seen, but the guru's gleeful grin is reason enough to worry about what's in store for Zoe moving forward.

For legal reasons, Masha appeared to refrain from drugging Zoe prior to her birthday. But now that she's officially 21, she's enjoying spiked smoothies just like the rest of the guests, and as a result, she's also seeing visions of her brother, Zach. The most curious part of this development isn't the visions themselves (after all, this is an episode with a scene where Lars literally gives birth), it's that Masha seems to know exactly what Zoe is seeing.

In the final moments of the episode, she whispers to Zoe in Russian: "He's here, isn't he? It's you. You're the key." This implies Masha wants Zoe to see Zach, but what's her endgame?

Is Masha Going Full Mad Scientist?

Right from the start, Masha made it clear that there's a reason behind everything she does. That includes deliberately choosing guests who compliment one another, and who fit within her larger plan for Tranquillum House. Additionally, she's experimenting with using illicit drugs as a form of therapy, and she's been accelerating the program for her current batch of guests.