Martin takes a red kite to Jake's live-in facility. In voiceover, Jake talks about how humans are hard-wired to share ideas. That's why we're constantly sending out signals and signs, and looking for them from other people.
In Baghdad, Abdul - the boy who nearly became a suicide bomber to get his family a new oven - hangs out with his pal Tarik.
Randall Meade - the ex-firefighter who believes he didn't save Martin's wife on 9/11 - sits outside a church in Lynchburg, his hometown. A newspaper headline shows "Lotto Winner Still Hasn't Come Forward." He's using his winning ticket as a bookmark.
Martin tells Clea that he's been officially informed that no trace of his wife's remains were found at the World Trade Center. He just wanted something, a piece of her to put in the ground. He considered going to the cemetery, but it's not the place for Jake. Clea disagrees. Jake should see that he misses Sarah.
In the cemetery, Jake runs off with the kite and his red notebook. Martin follows, meeting a stranger at Sarah's grave. Bobby explains he and Sarah became friends in the summer of 2001, when he was a bike messenger. As Martin goes to retrieve Jake, who's flying the kite, Bobby leaves.
Martin looks at Jake's notebook, where he's written "9.5" and drawn a clock showing 9:50. Martin's phone clock clicks to 9:50. Jake lets the kite go, then follows it. Martin trails him, spotting more instances of 9.5.
Tarik texts that band practice is at 9:50 tonight. Abdul tells a U.S. soldier he wants to perform at the embassy; Tarik has a metal band, Deep Lightning, and Abdul's the warm-up guy, like Chris Rock. OK, they can audition tomorrow. Abdul excitedly informs Lieutenant Laura Davis, who inspired him with the Chris Rock DVDs.
Randall listens to the young pastor, Steven Whitaker, fumble through his sermon. Afterward, the two men talk.
Jake zeroes in on the apartment of the puzzled Bobby. Convinced that they were meant to meet, Martin asks if the number 9.5 means anything to him? Jake bursts into the apartment, fixating on a little girl's photo. Why is Bobby's daughter named Sarah?
Lt. Davis and her translator, Corporal Shea, are wounded in an ambush. As they escape into the desert, she says a friend told her you can get anywhere you want, one footstep at a time. They start hobbling.
Randall tours the run-down church, built by Steven's grandfather, a gifted preacher. He ends up confessing about Sarah and winning the lottery with the numbers from that day. The basement staircase breaks, and they tumble down, trapped. Randall, unfazed, says the numbers reset his karma. That's why he's here. Whatever happens next, it's meant to be. Steven says his granddad got this look when preaching - just like Randall had when he said that.
Martin learns that Sarah knew Bobby had a little boy, and didn't think he should risk his neck on the bike. She tutored him in math weekly, to help him get promoted to dispatcher. It's a debt he can't repay. Bobby's also haunted that, although he was nearby on 9/11, he was too scared to help people - to help Sarah.
Martin also discovers Sarah hadn't been wearing her wedding ring.
Deep Lightning tap into an outside electrical line. Abdul messages the King Roadie website, asking what's the maximum feed for their ancient amplifier, so they don't blow up? Tarik tells Abdul that Chris Rock may have a message about the human experience, but unless Abdul says something of his own, he's just a parrot.
Jake climbs onto the fire escape, spotting the kite near the roof. He pulls the string, moving the satellite dish it's wrapped around - which belongs to King Roadie. His email warning Abdul not to go past 50 volts accidentally acquires a typo before being sent, changing "50" to "950."
Martin realizes Jake wants Bobby to get him. He warns Jake will go ballistic when grabbed. Jake snatches the kite, but falls - and Bobby catches him. Jake screams, but he's OK. And Bobby just repaid his debt.
Deep Lightning turns the amp to 950. Davis and Shea collapse beneath a power pole as the amp blows up the grid. The pole sparks, illuminating the soldiers' position. They're saved.
Bobby remembers something about the number 9.5 - September 5, his last session with Sarah. She showed up late, after another appointment.
Steven and Randall are rescued by a boy whose sister's been wounded in Iraq. She wants to talk to Steven. It's Lt. Davis, who says she kept going because she remembered what Steven told her in high school - about moving ahead one footstep at a time.
A soldier makes a snarky comment that infuriates Abdul. Like his hero Chris Rock, he turns his anger into biting, original humor. This is Abdul's audition. Tarik watches proudly.
In voiceover, Jake speaks of the human voice. We instinctively want to listen, in hopes of understanding it. It resonates differently from anything else. That's why we can hear a singer's voice over the sounds around it. We see Bobby and his happy family. A Lynchburg Times headline about Randall claiming the tri-state lotto prize. Randall, on crutches, meeting a real estate agent at the church. Steven sitting by Laura's bedside.
Martin finds September 5 in Sarah's 2001 datebook. Her appointment was with a jewelry store, which has kept her wedding ring all these years. She had it engraved with "1+1=3" - something she told Martin after Jake was born, because Jake made them a family. Now Martin has something to hold onto.