Season 10 starts in the aftermath of the DS9 novel The Soul Key, by Olivia Woods. The DS9 crew, and Captain Kira Nerys in particular, have just been through a complex and traumatic series of events involving the Mirror Universe, the Obsidian Order, the history of the Occupation, and the mysterious Gamma Quadrant aliens known as the Ascendants (these latter being the focus of the major storyline left unfinished by the publishing hiatus).
At the time I wrote these stories, this was the only version of the Ascendant storyline in existence, since the novel line was lying fallow. However since then, Pocket Books did eventually return to complete the storyline themselves, in the form of the 2015 duology Sacraments of Fire and Ascendance, both by David R George III. Pocket's official version of the story is at points wildly divergent from my own, and at times surprisingly similar.
NOTE: The 'cover image' is adapted from one found on Pinterest; it wasn't credited, or if it was I couldn't find it. If the image creator comes forward I am happy to credit as needed.