Isle of Man.
M/S of a group of young women students crouching beside a rock pool. C/Us of things being taken out of the pools and dropped into test tubes. M/S of Dr Joanna Kain on board a boat with a male companion. She is climbing into a wet suit. Narrator makes a joke about Joanna being "one of the most attractive sub-literal algologists working in Britain today." She is not a glamour puss by any means. A marine biologist, Dr Kain collects and studies seaweed. C/U of her putting on goggles.
Various shots of the good ship "Cypris" - operated from the Isle of Man - which is a research ship for the Port Erin Marine Biological Station. Various shots of Dr Kain getting into the water then underwater shots of seaweed. A water sample is taken from the sea. Dr John Slim takes temperature of the sea water and collects samples from different levels using a Nansen-Patterson bottle. Various shots of bottles being filled with sea water. Part of the work of the Port Erin Station is to examine the habits of scallops and herring.
Dr Kain surfaces and hands her colleagues a large piece of seaweed. Narrator states "another illustration of how modern techniques are being employed to study and improve our knowledge of the timeless depths."