Oceans have many secrets. Alien to man, they reluctantly open their possessions to him and severely punish him for any mistake. The oceans are endless, for this is the real universe. And therefore, despite the fact that humanity has been studying them for many centuries, they are still unknown and inaccessible, like thousands of years ago. Monsters of the deep - giant octopuses, squid, water snakes; inexplicably lost ships; "Quakers"; unidentified underwater objects... - another book of the series tells about these and other secrets of the oceans.