Close interrelations between plants and animals have developed during evolution. In Brazil one can find an extremely fascinating symbiosis: some flowering plants don't offer nectar or pollen, but a fatty oil. These flowers are called "oil flowers". The film shows the tight link between bees (Centridini) and their host plants (Malpighiaceae) in their natural habitat. By means of macrography and slow-motion all phases of the bees' complex collecting behaviour are documented, including microscopic shots of the bees' legs and their larvae. The flower structure is explained in detail. The film exemplarily introduces the basic mechanisms of a plant-animal interaction and the close connection between form and function in an ecosystem.