The Spanish-Portuguese crime drama mini-series "Operación Marea Negra" is based on real events that took place in the autumn of 2019. A submarine is heading to Europe through the Atlantic Ocean, carrying several tons of narcotics with three people on board. The travelers endure a storm, encounter ship malfunctions and hunger, attempt to resolve conflicts, and face pressure from law enforcement officials. The police are preparing an operation to seize the submarine.