The team sits in the hospital waiting room while Sam undergoes surgery for Murdoc's gunshot. On Christmas day, the doctor comes out and tells them that Sam said that she's sorry she spoiled their Christmas party.
Later, Mac and Jack are driving home and Jack says that they should take a minute to talk about the Christmas gift apparently from Mac's father. Inside are old World War II files. When they go inside, they smell a chemical just as Wilt arrives. Mac tells Wilt to come inside, and tells him and Jack that every door and window in the house has been wired to explode. He points out two recently-patched sections of drywall, and notices a surveillance Camera. Mac tells Jack that the Ghost is responsible and just turned the house into one of his bombs.
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In 2011 in Afghanistan, Mac and Jack are fighting while other soldiers cheer both men. As Mac pins Jack, Colonel Martinez comes in and orders both men to attention. Mac explains that he had noticed that Jack's bolt carrier was missing from his rifle and he was trying to fix it. Martinez tells Jack that Mac is his new EOD tech and Jack is Mac's new overwatch. He orders them to work together or he'll get rid of both of them, and walks out. Jack says that he was going to pin Mac's arm and has heard that he's a wunderkind, and points out that his training officer died on Mac's last watch. Mac says that he's heard that Mac has heard that no one else will work with him because of his attitude, and Jack tells him that he has 64 days until he ships home and he's not going to let anyone keep him from seeing Texas again. Mac agrees and says that after that they don’t have to see anyone else again.
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Police and FBI agents show up and Matty has them evacuate the neighborhood. Riley checks traffic cams to spot the Ghost, and Wilt runs back and Mac has said that no one can use a potential signaling device within 200 feet of the house. Matty has everyone move 200 feet back and Wilt explains that the Ghost cut off all communication into the house.
Mac saws open one of the drywall patches, and tells Jack that he inherited the house from his grandfather and is aid for, and that's why he lives there. He insists that the house isn't haunted.
Riley tells Jack about the Ghost and picks him up on a traffic cam. The Ghost enters and leave the neighborhood on foot.
Mac finds red wires and confirms that every door and window is rigged, including the secret escape hatch that he built. He then unscrews a light plate and confirms that it's not wired to a bomb, and then uses the outside lights to send a message in Morse code. It says to "Tell Riley photophone." Riley looks it up and discovers that it was an early communication device created by Alexander Graham Bell using light signals instead of electronics. Wilt gets a solar garden light from a neighbor to salvage the parts, and Mac sees them through the binoculars and confirms that they got his message. Mac then takes a boom box and wires the microphone into the lights.
As Wilt and Riley build the photophone, they hear Jack singing and can't turn it off. Riley uses the light from a police car to establish communication with them, and Mac tells Matty that he's going to start looking for the combs.
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Mac is working on a bomb hooked up to a hummer and gets his first complete glimpse at it. He has Jack open the trunk so he can get more light, and as Mac prepares to cut the wire, the bomb buzzes. Mac asks for chewing gum and a sat phone from Jack, and once Jack hands it over Mac uses the foil and the phone battery to burn the wire.
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Mac builds a device to trace the wires and their voltage back to their source. He finds the detonator beneath the floor and pulls up the boards, and discovers that the bomb is a lot bigger than he expected.
Outside, Riley discovers that she can't find any video feeds. She tells Mac and Jack, and Matty wonders why the camera isn't transmitting. Mac figures that the Ghost planted the camera so that emergency services would come there, and there's another bomb somewhere in the city and the one in Mac's house is a distraction.
Wilt and Riley pick up Charlie Robinson and explain what's going on. Riley says that Phoenix is working with the authorities to find the bomb but it's a big city. Matty is coordinating with the authorities, and she checks in with Jack. Mac is too busy to talk to her.
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Mac is searching for all IEDs and Jack points out that they haven't found anything and there's hostile locals all over the place. His teammate says that they need one more hour, but Jack reports that the place is clear and they're ordered to come in. Mac insists that there's a bomb nearby, and the last time he didn't follow his gut, someone died. He goes off and finds an empty can in an alleyway, and spots a man walking off. There's a bomb behind some barrels, and Mac goes to examine it. Locals confront Mac, and Jack shoots them down. Mac thanks him over the radio for helping him, and Jack tells him to hurry up and defuse the bomb.
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Mac is trying to ID the explosive, making a test of his own from kitchen supplies. He takes a sample from the surface of the explosive barrels to determine how much nitrogen is in it, and then tells Matty that the Ghost synthesized cubic gauche nitrogen, three times more powerful than MMX. He figures that the bomb is so powerful that a second bomb could take off half of LA.
They expand the search radius to all of downtown LA, and Charlie warns that the bomb could look like anything. Riley spots a garbage truck via sat cam and they carefully approach it. The LAPD has pulled all municipal trucks out of downtown, and Charlie warns that he doesn't know how to work a garbage truck. Wilt does and opens the back, and barrels of the explosive are inside. Charlie says that if the bomb goes off then a bomb disposal suit won't work, and he figures the Ghost is getting revenge for Mac stopping him a year ago. There are no motion switches and Charlie climbs inside to get a better look. He has no idea what half of the component do.
Matty tells Mac and Jack that Charlie is starting to disarm the second bomb. Mac goes to work defusing his bomb while Charlie checks the second bomb. As they open the case on the triggering device, red lights go off on their own and Mac has Charlie stop. He says that the bombs are linked by wireless receives. If Mac disarms his bomb then it will set off the larger one.
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Jack enters an abandoned apartment while Mac stays in contact with him over the radio. As he steps on a cloth, Jack hears a trigger goes off and finds the bomb under a nearby board. Jack tells Mac to stay away but Mac comes in anyway. There's 90 seconds on the bomb, and Jack tells him to get out because it's a lost cause. Mac says that he's going to watch Jack's back just like Jack is watching his, and tells Jack to trust him that he can diffuse it.
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Mac confirms that Charlie's bomb has a double relay, and says that they're going to have to cut the wireless link simultaneously. As they start to do so, Mac tells him to stop. He explains that the bombs have a direct wireless link, but they're talking through a radio link. That means that the radio link is smaller, and they can't cut both wires simultaneously. Wilt gets an idea and drives the garbage truck to Mac's house. They get there, driving through the barricades, and Matty tells the SWAT commander what they're doing.
Jack tells Mac that the second bomb is there, and Mac warns that there are still too many variables to simultaneously cut the bomb. He cannibalizes a DVD player and tells Wilt to break into the house next door and steal the DVR player. He then rigs up the scissors on his Swiss army knife to a circuit panel, and explains that he's hooked them up a to a light cell. Mac then says that they need mirrors and prisms, and Jack collect the mirrors.
Charlie hooks up a similar device and they back the truck up in position. Mac has Matty cut the power off in the area to stop any lights from prematurely setting off the cutters. Jack measures the distance and sets up a laser pointer, and Wilt cuts off the power. The truck is parked near the rear bedroom window, and Mac tells Jack that when they first met they couldn't imagine standing on a massive IED in LA. Jack thanks him for saving his life in Afghanistan, and says that there's nobody he'd rather die with. They shake hands and Mac goes to work. The cutters go off simultaneously and the two men go to work on the bombs.
The next morning, Mac and Jack come out with the trigger device and everyone cheers.
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Mac is preparing to head out, and tells Command over the radio that Jack flew out and he's waiting for his new cover. Jack joins Mac and says that he was ready getting to head home when he figures Mac couldn't get along without him. He tells Mac that he did it for his country, not for Mac, and Mac thanks him.
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Charlie has both bombs shipped to his lab in New York to find anything that could lead them to the Ghost. Jack tells Mac that he saw the gear from the watch, and points out that they match the tattoo on Mac's father's arm from a photo. He figures that Mac's father was trying to tell him how to find him.
Written by Gadfly on Jan 6, 2018