When no reaction occurs, Charlie, Larry, and Bill realize that the fire was intentionally set. Back at Charlie's house, Charlie and Don's father, Alan Eppes (Judd Hirsch), suggests to Charlie and Larry that the fires at the car dealership are two separate fires instead of one fire as Charlie and Larry were considering. While discussing the case at the FBI office, Don, Megan, Colby, and Charlie learn of a fire at an office building. This time, six firefighters suffer smoke inhalation as there was not enough water in the fire hose to put out the fire. When Ethan is brought in for questioning, he confesses to the fire. At the house, Alan demonstrates Pascal's law to Charlie and Larry, who are confused how a lack of water pressure could occur when the fire equipment registered normal pressure. Charlie determines that someone tampered with the office building's standpipe to create a lack of water pressure. Armed with the new evidence, Megan and Jake convince Ethan, whom Megan believes is innocent of committing the actual arsons, to tell the FBI who had asked for Ethan's help. Using Ethan's chat room account, which was obtained earlier in the investigation, the team traces Ethan's chat to a LAFD station. Charlie's analysis of the fires confirms the location and reveals that Stevens was behind all of the related arsons, including the fatal one at the car dealership. The team learns that Stevens was taking revenge on the LAFD as the LAFD rejected his application to be a firefighter years earlier. Don and the team confront Stevens at the same construction site where they confronted Jake. During the confrontation, Stevens attempts to escape, but accidentally bangs his head and an explosion occurs due to him carrying combustible white phosphorus, killing Stevens. At Charlie's house, Don breaks the news to Charlie and Alan that Ethan has accepted a plea deal in which Ethan would serve three years's prison time. Charlie, who had earlier in the investigation talked with Ethan about the difficulties of being child prodigies, confides in his father and brother that he possibly could have done the same things that Ethan has done. "Scorched" was series writer Sean Crouch's first produced television script. Originally from Colorado, Crouch knew of the Earth Liberation Front's (ELF's) involvement of the fires at Vail and based the ELM, the ecoterrorist group in the episode, on the real-life ELF. In developing the script, Crouch asked for assistance from people he knew.