His expression sobered to some extent, and I could see him shift into business mode.

Once on the other side of the music room door, Zoë's expression gradually sobered.

Starwind's expression sobered again, and he began to answer - but was interrupted.

Her expression sobered as she looked down at Meko's hands.

Cindy's expression sobered as she considered her sister's question.

Xabbu grinned, enjoying the happy moment, then his expression sobered.

She paused, and for a single fleeting instant her expression sobered.

Then his expression sobered, though he was still smiling.

He allowed himself an outer smile, as well, but then his expression sobered.

His expression gradually sobered as he considered her request.