Just the first sentence is the most unique start of a Zelda game ever. He is on an adventure because he himself is broken and needs a friend who can understand him. He's in a position to save the world because someone took the things closest to his heart away from him.
This is all thematic/conjecture and not actually part of the cause-and-effect. rising/falling action chain of the
plot.
That is, you could take away all of this and the game's story would still be intact. The world of Termina would still have a moon hanging over it; that'd still be a problem that Link, the hero, needs to solve; and the way to resolve it would be identical.
Healing sorrows is an integral part of the plot.
No, it's not.
Plot is a term that describes the
structure of a story; it doesn't describe the
message or
theme of the story.
The "plot" of MM (and its various sidequests) is basically:
- Bad thing happens
- Link shows up
- Profit
There's exposition that happens around this plot, but it's exposition. Exposition can have its own chain of cause-and-effect, but that isn't the "plot" of the work.
A Zelda game that is about helping others overcome their various sources of grief is easily the best Zelda game plot and storywise.
You do this in literally every Zelda game with NPCs.
You do this in Zelda II.
You do this in Link's Awakening.
You do this in Ocarina of Time.
You do this in Oracle of Seasons and Oracle of Ages.
You do this in The Wind Waker.
You do this in The Minish Cap.
You do this in Twilight Princess.
etc. etc. etc.
Zelda games are always about a hero showing up to put an end to some problem that is causing people tremendous grief and pain.
What's different about MM is that it makes it an integral part of the
theme of the work, not the plot.