The Scorpion Rules

Greta is the Crown Princess of the Panpolar Confederacy, a superpower formed of modern-day Canada. She is also a Child of Peace, a hostage held by the de facto ruler of the world, the great Artificial Intelligence, Talis. The hostages are Talis's strategy to keep the peace: if her country enters a war, Greta dies. The system has worked for centuries until Elian, a hostage from a new American alliance, arrives at the pretecture and disrupts Greta's quiet, structured world. Then Elian's country declares war on Greta's and invades the prefecture, taking the hostages hostage. Now the great Talis is furious, and coming himself to mete out punishment. Which surely means that Greta and Elian will be killed ... unless Greta can think of a way to save them.