The H-Bomb Girl by Stephen Baxter

The H-Bomb Girl is based on the Cold War in the year 1962.

  Laura, a fourteen a girl, has a key which can trigger a Nuclear War. She is advised that she has to use it when the worst of the worst of the came, though she didn't know what was this worst of the worst.
  In her new school she has made some friends and they come to know everything about her. They are also lured in the same danger as she is. Her form teacher, Miss Wells, looks very much like her and a waitress in a cafe, she frequently goes with her friends, has the same diary as she has. There was a stranger in her house in the room they had rented in their house in Liverpool. His name was Mort. He acted very strangely. One day, Bern, Joel and she found a strange device in Miss Wells bag. They all thought it was a phone because of seeing that sign on one of the sides. They also saw a driving licence dated 2007.
  At home, Laura saw a strange device hidden behind the books on the shelf. Laura thought it was a computer, but she wasnt sure. When an old man came to their home and he was looking just like Mort, her suspicions arose.
  Agatha, who was the waitress in the cafe, would call her Mum, and Laura was confused. Why would a lady, forty years, or more, older to her, call her Mum? Eventually she came to know that Agatha, both the Morts and Miss Wells were from the future. She came to know that Agatha would be her daughter in the future if this Cold War happened.
  Both, Agatha and Miss Wells, wanted the Key.
  When she was taken to Miss Wells, she came to know that the wanted to rule the past, present and future and that is why they wanted the Key. Agatha's future was destroyed because of the Nuclear War and she wanted it to improve it. Laura decided that giving the Key to anyone of them was useless and she destroyed it. Mort was furious with this action and pointed a gun at Laura as his future was also destroyed, the Key was destroyed and old Mort was destroyed. At the right time, her Dad came to the rescue. They picked up a gun fight with each other and, seeing that they had no chance of winning this gunfight, all the people coming from the future went back there and one of Laura's friend, called Nick, also went there. Bern, who was pregnant, was sent to a church and was living there. Agatha was trapped there. She helped Bern escape with her baby out of the church because they were giving the baby for adoption.

Its a very good book, telling us that we should never fear anyone and do what is right even if we get killed. Its a cool and adventurous book, telling us what will happen if there was a nuclear war. Every person, above the age of twelve, who is interest in History and Nuclear Power will enjoy this book.