The most common and most likely answer to this crossword clue is the 7 plus 8 letter word BERMUDA TRIANGLE
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More clues leading to the result BERMUDA TRIANGLE
- Friend, without hesitation, approaches a metal instrument that's feared by sailors?
- A Rembrandt concocted with guile and craft may go missing here
- Married but misbehaving, with view to getting lost here?
- Mystery surrounding Atlantic island takes shape
- Where fighter might disappear in corner after mad brute exploded before start of round one
- One of the British Isles needs alerting about possible danger area
- Surprisingly gain lumber trade in place of what’s disappeared?
- Area of mystery in novel tangible with a murder
- Product of confused dreaming, but real — a once-in-a-lifetime destination?
- Kind of shorts covering figure’s expanse in Caribbean
Buddy explains!

The straight part
We know that "mysterious area" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case mysterious area = bermuda triangle.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.