This is another story in the Full Metal Panic universe, set some years after the events involving Sousuke and Kaname. Ichinose Tatsuya is a fairly ordinary high school boy who lives with his father and his younger sister, Yukari. He has a habit of falling in love with foreign women, which has never ended well for him. One day, while operating a Power Slave in the mountains to assist with his father's company, he encounters yet another beautiful foreign woman named Adelina. He offers her help and is surprised to discover that she possesses a military Arm Slave called "Shadow." What is this mysterious, heavily armed woman doing in the mountains? Tatsuya's life is about to become much more exciting...