"The place that I grew up was a grey, unfeeling nothing. Then one day I heard your voice--and I knew for the first time that there is beauty in the world."
Soon the woman he loves committed murder then suicide.
It is a coming-of-age story, I think, in the description of Morse's affection for music, and to the soprano. Your role model or secret lover turns out to have conducted immense sin. Does this fact blemish all her glory, or is she still undeniably beautiful, and thus, occupies that secret place in you?
Morse seems to have chosen the latter, from the way that he kissed the soprano and cried uncontrollably when she died.
Nevertheless, the truth inevitably unfolds. The imagined land falls into pieces, gives way to a darker truth. The world now is not a bland nothingness, but all shades of gray, consisted of messy scribbles, oftentimes confusing.
After watching the pilot, I jumped to Season 4 to see the future Morse. He finally gets promoted in the last episode, after a good (or bad) 10 years of hard work. He now cares about a new woman, who dismissed him as being "some nice boy who won't try and put his hands up my skirt".
This is not a fairy tale where brilliance gets automatically promoted and virtue gets easily recognized. This is a description of the world we live in.