The 33 Miners....

Not sure it's the one you're looking for but it fits the clues....with your "minor" clue being a pun/homonym. :-) Scratch that guess.....I just read its from the 90's. :-)

I'll go with Batman Returns (or Batman & Robin) instead....thanks.

Missing in action = Reclusive rich guy
Long and lonely hiatus = Brooding alone in his cave
Minor assistance = Alfred or Robin.

My haiku to match yours.