Demon bombs are powerful explosive spells capable of killing demons. The recipe to create these bombs was recorded in the demon tablet by Metatron and was recovered by Kevin Tran. These bombs require ingredients from all over the world, including West Bank witch hazel, the skull of an Egyptian calf, and the tail of an unspecified newt on the verge of extinction. It is implied by Linda Tran that the way the ingredients are to be blended is intricate. When the bomb goes off, it destroys all the demons within the blast radius along with their meatsuits, leaving their shadows imprinted on the wall. The bomb does not appear to affect humans who are not possessed by demons.
Crowley takes Kevin to an abandoned warehouse to begin translating the demon tablet. Kevin reads from a chapter of the demon tablet and discovers the ingredients to create a bomb that destroys demons. He tricks Crowley and his minions into retrieving all the ingredients, telling them that the spell is to open a Hell Gate in Wisconsin. As Crowley waits in a field for the gate to open, Kevin sets off the bomb, destroying both of Crowley's demons and escaping with the demon tablet, leaving a dumbfounded Crowley in the middle of a field surrounded by goats while trying to talk to his recently deceased associates.
Linda Tran, unable to stand the constant hiding from Crowley, decides to hire a witch off Craigslist named Delta Mendota to retrieve the ingredients for the bomb. She tells Kevin that she told her to get the ingredients for the demon bombs, but didn't tell her how to blend them or the exact quantities necessary to make them. Linda checks in on Delta who is close to gathering all the ingredients for the spell and asks her about the recipe on how to make the bombs, but Linda refuses to expand on the subject.
Later, when Delta arrives at their hideout, she only gives Linda enough ingredients to make one bomb and demands payment before giving her what she promised. Delta leaves to go to the bathroom, but turns out to be a ruse to sell them both out to Crowley. She breaks a salt line and allows Crowley to enter and take Kevin while teleporting Delta somewhere else, leaving his demon minion to destroy the ingredients for the spell and kill Linda, who retaliates with holy water. She later calls Sam to explain everything and holds the demon captive until he reveals where Crowley took Kevin. She gives Sam the ingredients and Kevin's notebook filled with everything he needs to construct the bomb.
Sam, Dean, Castiel, and Linda arrive at the warehouse where Kevin is being kept. Dean kills the demon and heads inside along with Sam and Castiel, leaving Linda in her car. When a quartet of demons reaches Sam, he throws the demon bomb at the ground at their feet, setting it off and killing all four. Castiel is later able to save Kevin from Crowley and sends the Trans to Garth to keep them safe.
Dean and Castiel, planning to save Samandriel from Crowley, arrive at Garth's houseboat, where Kevin is working on translating his half of the demon tablet. Dean tells Kevin that he needs more "Demon TNT" to use against Crowley, which annoys Kevin as the ingredients are difficult to come by. Castiel asks for a list of the ingredients and teleports all over the world to recover them and even picks up Sam to help with the rescue.
While erasing the angel warding to allow Castiel entry into the warehouse where Samandriel is being interrogated by Crowley and Viggo, two groups of demons arrive and Sam and Dean light up their bombs and throw them into the hallways, destroying the demons when they are set off.
Ketch, while escaping the trunk of the Impala, finds a demon bomb in the weapons cache. He attempts to use it against Lucifer and Sister Jo, who teleport into a forest right before it goes off. Ketch explains to the Winchesters and Castiel that he had hoped the demon bomb would put a dent in Lucifer due his weakened state, not knowing that he had regained some of his power by repeatedly feeding off Anael's grace.