My Happy Marriage, Vol. 6 (light novel) — Akumi Agitogi

HER LAST STAND…After Naoshi Usui takes over the military and imprisons Kiyoka on false charges, Miyo takes it upon herself to save her fiancé. However, just before Miyo rushes headfirst into the military headquarters to stage an ill-conceived rescue attempt, she comes across a boy who is the spitting image of Kiyoka. Claiming to be Kiyoka's familiar, the boy urges Miyo to head to the Usuba estate and rethink her plan. From there, Miyo carves her own path to reunite with Kiyoka, delving into her family's past and rallying the few allies she can still turn to. But will this be enough to stop Usui once and for all…?