Yeah, so far the only people we've seen her interacting with are people who are most likely going to end up member of La Sirena's crew, so I can't see her disappearing.
I've got a new theory about the overall story for the first season at least.
After Hobus, the Romulans pretty much lose all of their power and most of them end up living as refugees other planets. Elnor (Evan Evagor's Romulan) and some others end up on Earth working for Picard, because he helped save them.
Another group of Romulans are desperate to recapture their old power, so they start experimenting with Borg and Soong-type androids. Perhaps they are trying to create some kind of Borg/Soong-type cyborg army, and Dahj (Isa Briones, the girl looking for Picard's help) is a test subject, perhaps they're first successful prototype.
Data comes into play because it turns out some of his programing was involved in the Romulan's experiment, and that programming combing with the Borg stuff makes Picard start to dream about him.
I noticed in the second trailer that the red outfits the androids are wearing is the same thing we see the people wearing in the scene with the sign about xxxx days since last assimilation, which is possibly on the Borg cube we see. So it looks like the androids are on the cube.
Seven, Hugh, and a bunch of other ex-Borg are going around trying to liberate other drones, and when they find out about the Romulans are up to they attack the cube they are on. This is where we see Seven shooting the two guns, and holding someone, possibly Hugh, in the new trailer. This is also where we see Hugh looking around the corner.
While there they stumble across Dahj and free her, after which she goes to Picard because her Borg bits are connecting them. Seven eventually tracks Dahj down to the Picard vineyard and that is where we see her talking to Jean-Luc in the first trailer. She eventually convinces him to protect Dahj. After finds out about the Romulan experiments, and that they involved Data's programming and the Borg, he decides to stop them.
He visits Dr. Jurati (Alison Pill) to check on Data's remains, which we see them doing in the first trailer, and she joins him on his mission once she finds out what's going on.
He then visits Starfleet Command, but when the admiral we see in the trailers refuses to help, he goes to the Rikers for help instead. Riker recommends Rio (Santiago Cabrera), the captain of La Sirena, and Musiker (Michelle Hurd), an ex-Starfleet special forces operative with experience dealing with the Borg and Romulans.
Picard, Dahj, Elnor, Musiker, Rio, and Jurati then all set out together on La Sirena to try to stop whatever the Romulans are up to.
Personally, I'm holding out hope that it will turn out the mastermind behind the whole Romulan/Borg/android plot will be Sela with a surprised appearance by Denise Crosby, but we've gotten no real evidence or rumors for that.
). It's Hugh's death that finally forces Seven off the sidelines.
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