Z Unit doesn't exist. So a knock on the door on Christmas Day brings more than one surprise to the special ops band of brothers.

Lincoln 'Ace' Kelly has traded everything for command of his unit and the girl who saved his life—even if she's furry and sleeps on the floor. Every year at Christmas the boys of his unit put extra chairs around the table for the ones they've lost.

Next year, Lucas expects to see new faces around the table and a whole lot more chairs.

When Hadleigh Rawson knocks on his door on Christmas Day, Lucas is reminded of what Christmas is about—gratitude for the band of soldiers who are more like brothers than employees, good food, better company and the hope that an old grunt might be worthy of redemption and love.