Time

Or so Penelope thought. 

Everything behind the register was completely foreign to her. She stared at it blankly; trying to remember what Percy said about how to operate it and couldn't equate what he said with the equipment in front of her. She was screwed. 

Thankfully there wasn't anybody in line when she took over from the previous cashier. All she had to do was stand there and try to figure this out. But she was afraid to touch anything and test it in case she accidentally messed something up. 

Penelope squinted at what was in front of her. There was a computer connected to the cash register and a card reader on the other side that was angled toward the customer. 

'Okay, these things aren't 100% universal but Percy told me about certain buttons on the screen that do different tasks…like preparing the machine to take cash or card payment and printing the receipt. It should be fairly straightforward,' she thought.