Since ancient times, the Earth has been a trading platform for representatives of other worlds. The Seven Great Trading Houses established offices here to sell and buy technology and resources. This is how the Exchange appeared. Selected people became the Guardians of the Exchange. Semyon Ardov, deputy director of the Exchange Security Service, finds himself involved in a large multi-move combination started by trading houses. And now he is no longer an operative, but a fugitive criminal accused of murdering an alien. He is being hunted by militants from great trading houses, his own office and modifiers, perfect murderers. He will have to find the real criminal, thwart the intrigue of the great trading house "Goliath", and also steal a precious artifact from the Dwarven Citadel. Desperate guys help him in this: a faithful partner nicknamed Balu and two dashing gnomes Kibur and Sigurd. The history of the Exchange begins...