The Outer Limits: The Probe

En route to Tokyo during a violent storm, a cargo plane crash lands in the ocean and four passengers miraculously escape from death. They drift on a safety raft and enter a spaceship that is used to analyze and study alien civilizations. The four people avoid a mutated and growing microbe, except one, and finally try to communicate with the distant alien race owing to a computer. After being disinfected and studied, they're released. By chance, a plane rescue them. On board, they see the spaceship which goes back to its home place and self-destroys in the atmosphere.