Penny had no idea where the chase would lead, although the truck seemed to be driving directly out of the city. From the slow rate of speed at which it traveled, she thought that it must be heavily loaded with cargo.
"If I only knew what was hidden under that canvas cover I might have the solution to the mystery," she reflected. "I think I have it anyway, but I must secure definite evidence."
Penny was fully aware that she had launched herself upon a dangerous enterprise. In some manner Joe Franey had lost track of her completely, and she could no longer count upon his protection. In an emergency she must depend entirely upon her own resources.
Before Penny had traveled many miles out of the city she began to grow alarmed because her gasoline gauge showed that she had scarcely a gallon left. Although she had her purse with her, it contained only a dollar. She could buy about five gallons of fuel, but should the truck lead her much farther into the country, she easily might find herself stranded.
Apparently, the driver ahead faced a similar need for gasoline. At the next filling station he turned in.
Penny determined upon a bold move. At the risk of detection, she too drove into the station.
"This will give me just the opportunity I need to get a good look at that driver!" she thought.
The truck had pulled up alongside of one of the three pumps but as Penny stopped in the shadow where the light from the filling station office would not shine fully upon her, she was disappointed to see that the driver's seat was empty.
"He's gone off somewhere," she told herself. "If only I could be sure he'd be away for a minute or two, I'd peep under that canvas cover and see what it is he's hauling."
Before she could transfer the thought into action, a filling station attendant came to serve her.