On the frozen island of Skane, the sky speaks. Beautiful lights appear on clear nights, and their colours have meaning: Green means all is well, and the Goddess is happy. Blue means a snow storm is on the way. And then there's red. Red is rare. A warning. Seventeen years ago the sky turned red just as Osa was born, unleashing a plague that claimed the lives of hundreds of villagers, including her own mother. This time, when the night sky once again bleeds crimson, she must discover what it means before so many lives are lost again.