what does 'the pie is opened' mean?

[manoeuvre]

In the TV series A Game of Thrones, Littlefinger boasts that he knows what Varys, the eunuch, is all about, and I am sure he was only pretending there.

Littlefinger smiled. "Leave Lord Varys to me, sweet lady. If you will permit me a small obscenity - and where better for it - I hold the man's balls in the palm of my hand." He cupped his fingers, smiling. "Or would, if he were a man, or had any balls. You see, if the pie is opened, the birds begin to sing, and Varys would not like that. Were I you, I would worry more about the Lannisters and less about the eunuch."

In the context, little birds are what Varys, the "Master of Whispers", calls his network of spies all over the Seven Kingdoms and perhaps beyond. The little birds supply Varys with much of his intelligence. Little birds sing, Varys knows.

Anyone can tell me why 'Varys would not like that' 'if the pie is opened and the birds begin to sing' and what's the figurative meaning of 'the pie is opened'?
Thanks in advance.

 

[Copyright]

You see, if the pie is opened, the birds begin to sing ...

It's an allusion to the nursery rhyme: Sing a Song of Sixpence, which has these lines:
Four and twenty blackbirds,
Baked in a pie.

When the pie was opened
The birds began to sing;

You might like to read the entire rhyme on Wikipedia, linked above.

Also see sing: to confess or act as an informer by telling the authorities about some crime or criminals.

 

[Barque]

It's a reference to a nursery rhyme: Sing a song of sixpence. The rhyme refers to blackbirds baked in a pie, that started to sing when the pie was opened.

I think he means that if he makes a move against Varys, Varys's spies will reveal information that Varys would not want them to (they will "sing").

Cross-posted.

 

[manoeuvre]

It's an allusion to the nursery rhyme: Sing a Song of Sixpence, which has these lines:
Four and twenty blackbirds,
Baked in a pie.

When the pie was opened
The birds began to sing;

You might like to read the entire rhyme on Wikipedia, linked above.

Also see sing: to confess or act as an informer by telling the authorities about some crime or criminals.

It's a reference to a nursery rhyme: Sing a song of sixpence. The rhyme refers to blackbirds baked in a pie, that started to sing when the pie was opened.

I think he means that if he makes a move against Varys, Varys's spies will reveal information that Varys would not want them to (they will "sing").

Cross-posted.

Problem solved. Thank you.