He's Chuck, and here are a couple things we should know: He's looking for his mom, Linda Hamilton, and Team Bartowski's helping. When he found out she's a bad guy and gave up, she called him. Now we're in a basementy-looking place with a security guard when Robert Englund lurks in, and jokes he's looking for the, uh, fitness center. The guy tells him to show his security ID, so Robert Englund sprays him with a fake inhaler. It makes the guy (and us) hallucinate, as Robert Englund tells the guy this is turning his life into a nightmare from which he'll never wake up. Shades of Freddy Krueger, for sure. Then he turns to a camera and brags about how well this works. Linda Hamilton opens the door and tells him she's impressed and has a buyer in Los Angeles who will be impressed. Then she makes that call from last week to Chuck. She wants to meet him in Griffith Park in one hour, but she wants him to tell no one and come alone, and she doesn't want to answer any of his silly questions such as why she left for 20 years. Sarah comes in then and tells him it's time for dessert, but realizes he looks like he's seen a ghost. He says he just talked to one.
An hour later, at what's presumably Griffith Park. She calls, and he says he didn't expect her to show up. But she's at his 3 o'clock; just had to make sure he came alone. He asks if she's afraid the bad guys she works for will see her hanging around her own son. She says it's much more complicated than that. Isn't it always with the Bartowskis? She asks him to meet her at the playground, and hangs up. He nods over at Sarah, hiding in the bushes, and they both head to the playground. Sarah gets there first and hides, but Mrs. Bartowski, a.k.a. Linda Hamilton, a.k.a. Frost puts a gun to her head. There's a lot of banter as they aim their guns at each other. Sarah makes accusations, and Frost gets angry. Chuck runs up and is all, "Mom this is my girlfriend; Sarah, my mom." Then he asks them to please not kill each other. Awkward! Just like all future mother- and daughter-in-law relationships. Aaaand ... Cake.
Their guns are still trained on each other after the commercial, but Chuck can see they're going to be "BFF Facebook buddies." Sarah asks if Frost honestly thought Chuck wouldn't come alone, and she sneers that she thought he'd trust her. In Chuck's defense, she did, you know... ABANDON HIM. He says he has every right to have a mother issue. She says he's absolutely right and lowers her gun, so Sarah lowers hers, too. Chuck rambles about what they'll do now that they're all hanging out. Then he starts to tell her a story about his tenth birthday. She stops him, though; she doesn't want to know anything about him. Sad Chuck: "Excuse me?" Frost says she's deep undercover, and will be tortured for any information, so she's better off knowing nothing about him or Ellie that could put them in danger. Skeptical Sarah tells her it's funny that she's undercover, considering there are no records of that, but Frost says they were expunged. Sarah thinks that's awfully convenient. Well, you know, probably not for Frost, actually. It would help her story to be able to access them right about now.