Theo jiggled his key in the lock for a moment before swinging the door open, gesturing for Izzy to walk through before him. She stepped inside, glancing around before turn back to Theo to raise an eyebrow at him.

As Theo closed the door, he jingled his keys in his free hand. “Did you know that most keys work by pushing little metal pillars around so you can rotate the lock? Gotta line up these little gaps so it can turn freely. To move the deadbolt back and forth.”

“No, but that sounds familiar. Maybe I saw a video somewhere.” Izzy sat down on the couch, setting her bag down beside her, and scrutinized the room as Theo continued.

“That’s why you need to replace keys eventually. They get too worn-down to get the little metal pin thingies in the right place. And if you wait too long, your new key won’t work either. All the peaks and valleys will be too low.”

“I see.” Izzy nodded, half-listening while looking around the room at the tasteful decorations and new electronics.

“Which means there’s only so many keys that can exist. The number is huge, but most lock smiths aren’t making random keys each time, especially for apartments. They all gotta be sorta similar to work in all the doors from outside to inside. Lots of commonalities.”

Izzy turned to see Theo closely examining one of his keys in particular. “So?”

“So.” Theo brushed the key with a thumb and them looked up to Izzy, smiling. “You can just file down a key a whole bunch and, if you’re lucky, open the apartment of a neighbor who’s on vacation.”

“Devious.” Izzy smiled and opened the huge bag she’d brought. “Let’s start with the video games. Those are easy to move.”