His expressionless mask slipped for an instant as he saw Honor.

Edwina had sunglasses on which turned her face into an expressionless mask.

She smiled, first time her face showed something other than a hard, expressionless mask.

He stood there for a moment, his face an expressionless mask.

Now her face was set in an expressionless mask.

It was as I expected: his face became an expressionless mask.

His face was covered by a grotesque white mask, expressionless and evil.

The lieutenant's expressionless mask gradually gave way to an expression of anger.

Conan kept his face an expressionless mask, though he was smiling inside.

One of the major challenges in the film was how to bring V to life from under an expressionless mask.