Centaur

"We may be in the Universe as dogs and cats are in our libraries, seeing the books and hearing the conversation, but having no inkling of the meaning of it all."

On a cruise through the Greek islands, a man encounters a handsome father and his son. He is strangely drawn to his fellow travelers, and discovers with some elation that they will all share a cabin aboard ship. Tricks of the light seem to join the pair into a single being when they walk ashore, and at times a third, much larger being appears to join them.