Dic: be in the dark (about something)

• The investigators admit that they are completely in the dark about the killing.
• I'm in the dark about who is in charge around here.
• I can't imagine why they are keeping me in the dark.
• She's in the dark about how this machine works.
• I'm totally in the dark. I don't know what's going on.
• We're still in the dark about whether any jobs are going to be cut.

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1. If you are in the dark about something, you do not know anything about it.
2. Fig. uninformed about someone or something; ignorant about someone or something. (*Typically: be ~; keep someone ~; stay ~.)
3. to not know about something that other people know about. (often + about )

... Cobuild, McGrow-Hill Idoms, Cambridge Idioms