She remained at her seat by the window. Several times she was tempted to pick up a magazine and read for a few minutes. She resisted the impulse, remembering that she had heard her father say that a good investigator never took his eye from the place or person he was watching.
Another hour dragged by. Penny grew tired and bored. It was a warm night and the tiny room had become oppressive.
"I'll wait a little while longer," she decided.
Penny ate the last of her sandwiches and wished that she had bought coffee instead of milk. It would have helped her to stay awake.
Suddenly she became alert. A man stood in the doorway of the Brunner garage alley entrance. She did not need her father's field glass to see that it was the manager. He looked at his watch, then cast a glance up and down the street.
Penny studied her own wrist watch. It was exactly ten o'clock.
A garage service car rolled swiftly down the street. It swerved into the alley.
Simultaneously, Brunner swung wide the rear doors of the garage. The truck drove in, but not before Penny had riveted her eyes upon the license number.
At sight of the last three figures, her heart leaped. The numbers—684—were identical with those she had noted upon the license of the service car at the Big Dipper!