The twins decide to come early, so Eugenie undergoes an emergency C-Section, and they both turn out to be healthy, but require some time in NICU before she can take them "home". Just as she's about ready to do that Roland visits with news that her kingdom and many of the others in the Otherworld are under a spell keeping them in unnatural winter (shades of Narnia!), likely cast by the queen of the Yew Land, Lania?? She decides to return immediately to see if she can save her land, and bands together with Dorian, Kiyo, Jasmine and some of her underlings on a quest to break the
The saga does mostly wrap up in this novel, but not so tightly that Mead couldn't bring the series back to life if it were necessary, or inspiration struck. All of the same potential for conflict with other faerie rulers and personal drama still remains, the only thing that's settled - somewhat - is the Storm King's progeny's prophecy.