Awesome's at home alone, starting to switch out the hard drive on Ellie's dad's computer. Which is a perfect time for her to come in and tell him about her epiphany today. She says she thought about how Clara's learning stuff so fast, and realized her dad was trying to figure out a way to input knowledge into the human brain without having to learn it. She says she knows her dad left her this knowledge for a reason, but she doesn't know what to do with it. She just wishes her dad were here. Awesome agrees and slips the fake drive into his back pocket.
Castle. Sarah and Chuck grill all of the suspects in Brody's murder. He tells Robin Givens that she wanted his program to fail "and... you've said very mean things to me all day." She says she'd never do anything like this, but he reminds her she's already gone after his sister, so she'd do almost anything. Jody cries about how emotional she's been since her boyfriend broke up with her. Chuck feels bad, but Sarah tells him not to fall for the psy-ops expert's psychological manipulation. But Chuck, a sensitive soul, cannot help it. Damian screams about how they're torturing him, I guess because he's injured and being grilled. Chuck asks why Damian's bag is covered in sand, which is a convenient way to block X-ray equipment. Damian says it's because everything he owns is covered in sand thanks to the CIA sending him to every freaking desert. Chuck pulls a boom box out of Damian's bag and compliments it for being "old-school." Damian says it doesn't even work. Because there's sand in it. Chuck says it's suspicious that Lewis is a tech guy and a bomb specialist. Plus, he says that Lewis knew Brody was his first choice and Lewis was his second. Lewis says he actually didn't know that, but thanks for not choosing him. Sarah pulls a giant knife out of Lewis's bag and Chuck asks him to explain it. Lewis: "Uh, it's my knife." Chuck asks why he has a knife used by an IRA bomb maker in his bag. Lewis: "Because I killed an IRA bomb maker and I took it from him."
When they're done, Chuck tells Sarah the only thing certain is that the killer sat in that interrogation chair. Sarah's not even sure about that, but Chuck notices a bomb under the chair and says, actually, he's pretty sure. He tells Sarah they've got to go now, and they get out of the room just as it explodes. Upstairs, Jeffster!, sleeping in recliners, shake a little. Lester asks if Jeff felt that, but Jeff hasn't "felt anything in years." Back down in Castle, Chuck and Sarah come to and can't hear anything. Casey finds them and tells Walker he's glad she's alive. Chuck, offended, says it's good to see Casey, too. Casey tells them Damian took another piece of shrapnel this time, but he'll still have to wait for a doctor. Robin Givens and Jody are both right there with injured Damian, but Lewis is missing. They figure it must be him, since he's he bomb expert. Chuck's disappointed that his second choice would be the killer.