The TV series "Nightsleeper" is a dramatic detective thriller about the passengers on a train hurtling towards disaster. The sleeper train departs from Glasgow to London. In addition to regular passengers, there is a British government agent on board, carrying out a secret mission. He is the only one who knows that the train is not destined to reach its destination, as a carefully planned terrorist attack awaits it along the way. The only way to prevent the tragedy is to take action from within, saving the sleeping people one by one.