Beyond the Gate

Marshal Cage Stone and Keeper Sabelline Shelton enter the caverns beneath the mountains overlooking Sulbreth, intending to reset the magical seals keeping the otherworldly demons at bay. But from the first, their carefully mapped plan is dogged by mysteries and dangers their training hasn't prepared them for.
King Jonared pushes aside his guilt at sending Cage and Sabelline on an apparent suicide mission. He has trouble enough with the demons spilling out of Kingdom's Gate and his opportunistic cousin who is using the battle to try and steal the throne.
Cage and Sabelline stumble onto a shocking discovery deep beneath the mountain and soon they're running for their lives. If they do they duty and reset the magical seals, it may mean they'll be trapped forever in the lightless caverns. Their only hope of survival rests on Cage's acceptance of his heritage and Sabelline's iron determination to return to Futhark and the families they left behind. All Cage must do is give up his human soul.