A film about a scientific expedition to the Seychelles to study coral reefs. The map on which the route of the expedition is drawn (animation). The ship "Professor Bogorov" is on the way. Feast of "Neptune" on the deck of the ship; newcomers to the expedition are awarded a certificate of crossing the equator. Republic of Mauritius, Port Louis. Transport traffic on the city street. Policemen are standing. Movie posters. Pomplemus Botanical Garden; lake in the garden; elephant turtles; shrubs. The streets of the town. Scuba divers dive into the ocean from a boat. Coral bottom view; the scuba diver takes pictures of corals, schools of fish swim in the corals; the scuba diver takes a water sample with a special device (underwater filming). Republic of Seychelles, Victoria. Port view. Bank building on Seychelles street. Cemetery. Monument to the researcher of the tropics and educator P. Poivre. Sale of souvenirs on the streets of the city. Coconut palms. The scuba diver swims under water; a school of fish in a lighted space; the scuba diver collects various exhibits from the bottom (underwater filming). Researchers examine the corals on the deck of the ship.