On Halo Tides (en Inglés) - Bennett R Coles

The winds of war are growing, dwarfing even the fiercest solar storms. The star sailing ship HMSS Daring is running at full sheet as His Imperial Majesty's Navy assembles for battle against the alien Sectoids. Commander Lord Liam Blackwood and Petty Officer Amelia Virtue have encountered many foes, but even they aren't ready for what faces them now.

As Daring gets swept toward the looming war, Liam and Amelia must uncover the motivations of the mysterious aliens before the fleet crosses a line from which there is no returning. But the treacherous nobility in the fleet reveals its own adversaries who threaten Liam and Amelia like never before.