...Prison of the distant future. Artificially recreated distant primitive past of humanity. A primitive world ruled by the descendants of the first “exiles,” who have long gone wild. Now a new person appears in this world. A man whose task is to find, at any cost, an escaped dangerous criminal who has managed to find a solution to the mystery of the Glass Prisms - the sources of energy in the “convict world”. But won’t the price of capturing the fugitive be too high?..