While having a retired fireman check his smoke detectors, Monk witnesses a murder for what could prove the final time when the escaping killer throws an acid mixture in his face. Deprived of his sight, Monk feels useless. Can the detective crack the case and prove to himself he's still got it?
This episode includes examples of the following tropes:
- Adaptation Name Change: As an adaptation of the novel Mr. Monk Goes to the Firehouse.
- Sparky, the firehouse Dalmatian of the novel, becomes retired firefighter Rusty.
- Lucas Breen becomes Peter Breen.
- Esther Stoval becomes Stefanie Preston.
- Cold Open: This episode marks a rare occasion when Monk is present for the murder. The opening shows Eddie Murdoch killing Rusty and then blinding Monk when he comes to investigate.
- Compressed Adaptation: Mr. Monk Goes to the Firehouse was a much longer book and was about Monk investigating the death of a firehouse Dalmatian and an arson murder that turned out to be connected, while having to temporarily live with Natalie and Julie as his apartment is being fumigated. Understandably, a lot of that material can't fit into a 42 minute episode, so the plot is streamlined to just the core of the murder mystery.
- Crime After Crime: Construction foreman Peter Breen bribes Eddie Murdoch to kill his mistress Stefanie Preston, and gives Eddie his keys (including one to her house) so he can get in. Murdoch strangles Stefanie, spills rum to make it look like she had been drinking, then sets her house on fire by lighting a pile of old newspapers with a cigarette. After leaving, though, Murdoch realizes that he's left the keys behind. In order to be able to sneak in and get them, he plans to steal a firefighter's coat and helmet from the nearest firehouse and use them as a disguise. He ends up killing a man and blinding Monk with cleaning solvent, grabs a coat and helmet, and later discards them after retrieving the keys. He either falls or gets pushed by Breen off the top of a building framework to his death, and Breen goes on to assault Stottlemeyer before Monk shoots and kills him. The final tally: one arson, two murders (three, if Breen pushed Murdoch), two assault-and-batteries (one against an active police officer), one petty larceny, and one impersonation of a firefighter.
- Decomposite Character: In Mr. Monk Goes to the Firehouse, Lucas Breen personally killed Esther Stoval and Sparky. in the episode, Peter Breen hires someone else, Eddie Murdoch, to commit the murder.
- Disney Villain Death: Eddie Murdoch dies from this while trying to chase Monk, courtesy of being pushed by his boss.
- Everyone Has Standards: In an argument between Monk and the drifter suspect about their respective wives' deaths (car bomb and pneumonia), Monk asks Natalie which death is more worse. Understandably, she is hesitant to answer the question for fear of offending the widower she chooses against.
- Eye Scream: Monk gets splashed with a detergent and acid solution, which temporarily blinded him. There is also a Gross-Up Close-Up of his damaged eye when it gets examined.
- Faking the Dead: Peter Breen hides as just another corpse in the morgue until the coast is clear and he can get his keys from Murdoch's body.
- Five Stages of Grief: Initially Monk spends most of his time near-catatonic with depression, but when he realizes blindness allows him to ignore a lot of disgusting things, he lightens up near-instantly. The skipping over of the intermediate stages worries Dr. Kroger, who thinks Monk is using the disorder to further isolate himself from the world and that the backlash when his glee lessens will be significant.
- Found the Killer, Lost the Murderer: Monk finds Eddie Murdoch, the man who attacked him at the firehouse and killed Rusty, at Peter Breen's construction site. Murdoch, in trying to chase Monk, ends up falling down a shaft to his death. They identify him as the man who killed Rusty and Stefanie Preston, but Monk doesn't believe that Murdoch had any reason to kill the arson victim (his reason for killing Rusty could be that he panicked), and realizes that Peter Breen must have paid Murdoch to do the killing. Then Breen comes after Monk and Stottlemeyer to get back the incriminating keys, allowing Monk to bag the murderer as well.
- Funny Background Event: There's at least one shot in an alleyway where you can see a prostitute standing behind Monk, though she has her back turned and she isn't paying attention to the good guys.
- Groin Attack: Monk almost hits Randy with his guiding stick at one point as a quick gag.
- Heroic BSoD: Zigzagged. Monk is initially broken-hearted that he's possibly lost his sight, convinced that he's presently the most miserable man on earth. Then he starts to see the silver lining in his blindness, to the point where he becomes proud of it. However, Monk's new-found confidence in his blindness plummets after an embarrassing incident, where he panics while mistakingly thinking he's up high on a cross beam without a floor (when the cross beam is actually sitting on the ground).
- Ignorance Is Bliss: Due to being blind, Monk is unable to see everything that would disgust or aggravate him, leading to feel being blind was good. As he put it "Out of sight, out of mind".
- It's Personal: The SFPD treats the murder of a fireman with the same level of seriousness as they would the murder of a cop.
- Misery Poker: Monk and the drifter try to trump each other's misfortunes. Monk insists he wins and yells that he'll take on the whole department at once, as he couldn't possibly lose. Then he breaks down crying.
- Mugged for Disguise: Eddie Murdoch kills Stefanie Preston on the orders of his boss Peter Breen and sets her house on fire. But he leaves Breen's keys behind and doesn't realize this until it's too late to go back in. To get back to the fire scene without drawing attention, he goes to the nearest firehouse and steals a firefighter's coat and helmet to get back into the scene, killing an ex-fireman and blinding Monk on the way.
- Oh, No... Not Again!: When Monk enters the firehouse carrying a container full of his smoke alarms for the firefighters to test, the fire captain groans about him coming back.
- Running Gag: Early on, Natalie mentions Mr. Magoo as a blind person who accomplished a lot (claiming he was an inventor). The name keeps popping up through the episode.
- Shovel Strike: Eddie Murdoch walks into Fire Company 53 to steal a firefighter's coat and helmet. As he is grabbing it, a firefighter named Rusty comes around the parked fire engine to confront him. Murdoch responds by grabbing a shovel and striking Rusty over the head, killing him. Seconds later, Monk comes around investigating the audible clang caused by the first hit, and Murdoch swings the shovel at him, though Monk dodges a would-be-lethal blow so that it hits him over the back. There is a struggle, and Monk grabs the shovel, but before he can swing it at Murdoch, Murdoch throws a container of acid in his face, blinding him. Monk drops the shovel and staggers backwards against the fire engine screaming in pain.
