The term “emotional stakes,” has been thrown around a bit regarding this year’s Arrow-verse crossover, and with this new information, it appears as though it will involve Kara and Alex.
Perhaps Alex might be placed in some real danger, which typically doesn’t end well in the Arrow-verse, or something happens between the sisters that puts their relationship on ice for a bit.
As Andrew Kreisberg mentioned, there are already plans for the Danvers sisters to have an episode dedicated to their strong bond in Season 3 of Supergirl, and now that we know they’re the focus of the crossover, one has to wonder if the early half of this season is all a build up to some crazy moment happening in the crossover.