On the beautiful world Adalta, an ancient threat emerges. Young Marta is dropped to the planet for her first secret mission alone. Raised by her father on an orbiting trade ship, he trained her for this - and to live by two rules: Don’t get attached. Don’t get discovered.

As cover for her mission, Marta joins the Mi’hiru, the all-female elite guard who patrol the skies on Karda, majestic hawk-headed flying horses.

On this planet where the only weapons allowed are arrows and swords, Marta discovers a high-tech weapon she knows could only come from her ship. Someone is smuggling them to use in the bitter power struggle between two noble brothers. She knows she must stop this threat, and she reluctantly joins forces with the handsome but arrogant Altan. As their connection grows, Marta struggles to keep her secret and to keep the rule of not getting attached.  

As tensions rise and the ancient threat grows, will Marta accept the frightening elemental magic powers Adalta wants to give her to save the planet she loves?