Construction of tunnels along Lake Baikal during the construction of the Baikal-Amur Mainline. The builders of the 16th tunnel detachment are working. Explosion of soil rocks. Removal of rock by MOAZ trucks. A research vessel is sailing on Lake Baikal. Taking a water sample. Construction of treatment facilities in Severobaikalsk. Meeting of Tunnel Builders of the 16th Tunnel Detachment; issues of protection of the coastal zone of Lake Baikal, punishment of ecology violators are discussed. Head of the chemical laboratory F. Tumorov speaking. The hero of the film is a foreman of MAZ drivers, a public inspector for the fight against poachers, D. I. Pedan, works on a construction site, makes a round with dogs in the taiga. DI Pedan judges the competition of fishermen-lovers of ice fishing. Public construction of fishermen and hunters from among the builders of the 16th detachment: the construction of the House of the fisherman and the hunter. Rally of workers on the occasion of the completion of the construction of the tunnels. Monument: MOAZ on a pedestal on the highway on the shore of Lake Baikal.