Flashback. Dr. Beauregard tries to get information from Petty about the final land mine. This involves submerging him in a tub of ice water. Lucy watches with disdain. Warden James isn't so bothered, but eventually agrees to let Lucy try things her way.
Present. Rebecca and Doc show a picture of the shrapnel to a guy at what looks like a military surplus shop. He tells them it's a Silver Star. Right in front of this guy, they start talking about the case. Petty didn't get any medals for Korea, but he thought he deserved one and wrote a lot of letters to the government about it. Rebecca figures he's planting the bombs as payback. He probably got the medals from soldiers' graves at the Presidio. They dash off to chase down their next clue, leaving the surplus shop guy with the unlikely mental image of some 80-year-old codger planting land mines around the city.
Meanwhile, Petty is holed up in a tomb, polishing one of his ill-gotten medals. A guard walks in. Petty stabs him.
The next morning, Doc and Rebecca show up at the Presidio. Doc says Petty's original stash of mines was never found. Rebecca figures out in all of five seconds that the mines were hidden in the tomb.
Flashback. Lucy hands Petty a cup of hot tea, which he drinks gratefully. "Now that's how you treat someone when you want something, Warden," he says. Lucy calmly explains she drugged his tea. "Just a mild sedative to help you relax," she says. His facial expression goes, "Aw, shit." Lucy switches on a reel-to-reel recorder. She recites a list of his wartime accomplishments, like clearing several minefields by himself. His fellow soldiers were awarded medals, but Petty went without. She recounts how he then killed children, whom he calls "little soldiers." Lucy straps him into a chair and places electrical contacts at his temples. She places a rubber guard between his teeth. She gives him a short jolt of 55 volts, then removes the apparatus and guard. He starts singing something in Korean.
Later, Lucy plays the recording for Tommy Madsen, who is also a vet from the Korean War. She wants to ask him a few questions, but he has questions of his own. He wants to know why he spends so much time in the infirmary, for starters, and why they're taking so much blood from him. He makes a deal with her: He'll tell her what the song means, if she finds out why he's in the infirmary all the time. She agrees and he says the song is a lullaby. The Koreans used the lyrics to tell each other where they'd hidden the mines. They were in the fields where they once played. They had to stop in their tracks, for fear of walking on the mines they'd laid. Tommy says that one word in each line would point to a different location.