Unaware where the bulbs have gone? (2,3,4)

I believe the answer is:

in the dark

I'm a little stuck... Click here to teach me more about this clue!

'unaware' is the definition.
(I've seen this before)

I don't understand the remainder of the clue.

(Other definitions for in the dark that I've seen before include "Without information" , "Told nothing" , "Ill-informed" , "without being told" , "Ignorant, unaware" .)

I've seen this clue in The Guardian.

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