While working to make the new USS Enterprise-A's systems functional, Montgomery Scott is contacted by Dr. Gillian Taylor, who informs him that the humpback whales George and Gracie have developed a mysterious illness which has caused brown streaks to appear on their skin. Scotty beams the whales up into a new tank in the Enterprise's cargo bay so Taylor can work on the problem there. With the assistance of Uhura and Spock, Taylor and Scotty determine that small amounts of pollutants need to be added to the water in which the whales are living. When George and Gracie's life signs continue to fall, Scotty completes the cure by playing his bagpipes to relieve the whales' loneliness and encourage them to sing.