The phrase "her eyes were a sunless sea" in paragraph 5 of "Kate's Vigil" is a metaphor that conveys Kate's sadness and loneliness. The phrase suggests that her eyes were dark and empty, like a sea without the sun's warmth and light. Two details from the story that support this interpretation are that Kate was "lost in her own thoughts" and that she was "unable to find solace in the world around her".