It's spring—a time for new beginnings. This is Miki Yoshida's final year of high school, and she's determined to make this the best year yet. Miki is in control ... . . until Hiro Sakurai shows up. The tall, handsome new student is hiding something, and Miki wants to know what. As she breaks down Hiro's defenses, she is unnerved by how much she cares about him. Too bad he is the one guy who can't care for her back. But Miki is falling for Hiro, and nothing's going to stop her from getting close to him—not even his dangerous secret.

Has Miki fallen too hard? It's summer, and Miki Yoshida is learning all about love. Her senior year has blossomed with promise ever since she gained Hiro Sakurai's confidence. Now, she's resolved to keep his trust as he reveals more about his secret mission and warns: "Don't get involved." But Miki fears his work might do more harm than good, and she takes control—with disastrous results. How can trying to make things right turn out so dangerously wrong?

Is their secret safe? It's autumn, and Miki Yoshida's life is finally settling into a routine. She and Hiro are spending all their time together, and Miki couldn't be happier. There's just one problem. Hiro's breaking all the rules to be with Miki, and the more time they spend together\-\-and the more they fall for each other\-\-the more there is at stake. With jealous Reika on the prowl, Miki knows they can't hide forever.

Can love survive? It's winter, and a bitter chill of desperation has settled over Miki and Hiro. Far from home, the young couple treks through the frozen north, with Akuzu's powerful agents hot on their trail. Miki knows they are determined to tear her and Hiro apart. But she has different plans. With the help of an unlikely ally, Miki and Hiro endure a daring journey, battling freezing conditions and frightening forces just to be together. Miki is certain they can make it, hoping that love really does conquer all.