The most common and most likely answer to this crossword clue is the 6 plus 3 plus 6 letter word HANSEL AND GRETEL
I've seen this crossword clue in The Times
H
A
N
S
E
L
A
N
D
G
R
E
T
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L
More clues leading to the result HANSEL AND GRETEL
- Fairy-tale siblings represented in Helen’s grand tale?
- Two kids lost? New angle: three lads lost!
- … has learnt legend about children abandoned in forest
- Opera North in Leeds Grand enthral a screwball
- Fairy tale, a legend, enthrals when broadcast
- The England Earl’s sadly doing for fairytale characters
- For a change all then see grand opera
- Agnes enthralled unhappy fairy-tale children
- Forest wanderers reset Neanderthal’s leg
- Chinese dynasty legends later become a children’s story
Buddy explains!

The straight part
We know that "Fairy-tale siblings" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fairy-tale siblings = hansel and gretel.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.