A mysterious anomaly occurs off the coast of Cuba – a huge tornado draws in all the water, draining the ocean. The Soviet rules have sent Belka and Strelka on a recon mission to the island of fraternal peoples. The old friends will see the beauties of Cuban nature and the azure expanse of the ocean, and the underwater world shrouded in secrets. They have to go through a series of dangerous adventures that will not only lead them to unravel the Cuban anomaly, but also test their friendship.