When an elite, covert military intelligence unit experiments with a highly classified operation -- a high-tech spherical device code named Back-Step, CIA castoff Frank Parker is chosen to travel back in time on clandestine missions to avert present day disasters, but he has just seven days to achieve each mission. Donovan, the project's chief military advisor whose life Parker once saved, is a strong supporter, as is scientist Olga Vukavitch. The only member of the selection committee opposed to Parker is Nate Ramsey, who is convinced he's the wrong man for the job.