Like a Calling: An F/F Omegaverse Sci-Fi Romance

The Sworne have returned to the Milky Way!
The Sworne arrive in Kander's airspace and demand only one thing; the surrender of all Earthlings for termination. Upon Kal's refusal, fighting ensues and hostages are taken on both sides until Kal and Charlie win the skirmish, forcing a ceasefire. The Sworne offer an exchange of hostages, a trade of resources, and a promise to depart the solar system, if the Sworne keep their word.
Charlie and Kal accept that they're not prepared to challenge their enemy today, needing time to obtain more weapons and allies for the impending war. Together, they lay plans to prepare Kander for war including seeking allies. They are left with one worrisome concern: will an alliance with Serrato Corps be a necessary evil?