"In a nutshell" and "Get to the heart of the matter" are both fairly commonly used phrases in the U.S.
Those, and most other suggestions would work and communicate the following message adequately.
I'm looking for something with a little more finesse. Maybe playful or tongue in cheek.
Usually, I find myself looking for a Norwegian term that could substitute an english idiom. I think the english language is far more abundant with colorful phrases than my own language, both intelligent and low brow variants.
I bet you guys have the equivalent to what I've mentioned at the top.
I remember listening to a radio interview with some american writer who commented on one of his characters: "He's in a place the buses don't go…" - Priceless
