Film for everyone ends in threesome, synopsis wrongly explains (10)

I believe the answer is:

misteaches

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'wrongly explains' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.

'film for everyone ends in threesome synopsis' is the wordplay.
'film' becomes 'mist' (to film over is to mist or fog over).
'for everyone' becomes 'each' (I've seen this before).
'ends in' indicates one should take the final letters.
The last letters of 'threesome synopsis' are 'es'.
'mist'+'each'+'es'='MISTEACHES'

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I've seen this clue in The Independent.

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