A nine-year-old autistic savant named Simon Lynch (Miko Hughes) is given an adult puzzle book by his teacher, and deciphers a phone number in a numerical puzzle. It was published in the magazine by two National Security Agency code creators, Dean Crandell and Leo Pedranski, to see if anyone could decipher it. The code called "Mercury" is allegedly so complex that its creators believe no computer on Earth can decipher it. Simon phones the number and the NSA division chief, Lt. Colonel Nicholas Kudrow (Alec Baldwin) realises the boy's ability to decipher the code is a grave liability. He dispatches two assassins, Peter Burrell and Shayes, to terminate the boy and his parents, named Martin and Jenny Lynch.
