A space probe visits Earth and threatens to destroy it unless it hears the song of a humpback whale. Since they are extinct, the Enterprise crew travels back in time to find some.A space probe visits Earth and threatens to destroy it unless it hears the song of a humpback whale. Since they are extinct, the Enterprise crew travels back in time to find some.A space probe visits Earth and threatens to destroy it unless it hears the song of a humpback whale. Since they are extinct, the Enterprise crew travels back in time to find some.