Serena Valentine isn't your average sixteen-year old girl. She's determined, stubborn, and decisive. She also happens to be an agent of the ICI; a spy commission only the government knows about. When Serena is assigned her first mission, it's the opposite from what she was expecting. Serena must go undercover as a high school student at the school of Summington. She'll have to deal with her team, the craziness of high school, and the real definition of spy. High school was not anything Serena was expecting. But when you're a spy, you have to be ready for anything.

"This summer will be our legacy. This will be what you will be remembered by. This will be the story you tell your grandchildren about when you were in high school. We're going to travel to places we never thought existed. We're going to do things we never even thought were possible. Things that we never dreamed about doing, this is the summer." Crestview High is an average high school in an average city with people who live average lives. Except for one thing, of course: Their senior tradition of riding a bus around the country for the whole summer after graduation. Not just a normal bus, an old school bus that the Belton family bought years ago and ever since their first son graduated, they've carried on the tradition. Now, the youngest and only girl of the family is graduating Crestview, which means that Alaina Belton is determined to live up to the Belton name and make this summer memorable for all twelve people on the bus this year. Of course, with twelve celebratory teenagers under one tiny roof for two months, there is bound to be love, drama, regrets, and a few memories to be made.