It's late at night in a major hospital, and everything is quiet. Nurses are at their stations, a janitor cleans, patients sleep. An old man shuffles down a hall, into an elevator, and right into the office of Dr. Graydon Whitcomb. With an amazing burst of strength and speed, the old man lifts his oxygen tank and swings it at Dr. Whitcomb's head! He connects " again and again " making sure the doctor is dead. Then he shuffles his way out and returns to his room as quietly and inconspicuously as he left.
The next day Monk shows up at the hospital with his own medical emergency - a bloody nose. Natalie has to leave for a date, so Monk is left alone, surrounded by germs and illness. His seemingly incurable nosebleed leads him to seek out Dr. Whitcomb, the hospital's chief of neurotrama. Entering Whitcomb's office, Monk bumps into a coffee table, and then into the dead body of Dr. Whitcomb!
Stottlemeyer and Disher soon arrive to join Monk at the crime scene. Their only clue leads them to Hank Johansen, an elderly, bed-ridden patient. Hank's oxygen tank was the one used to kill Dr. Whitcomb, but Hank can't be the killer. The old man can barely get out of bed, let alone kill someone with an oxygen tank.
Our trio moves on to question Hank's primary physician, Dr. Davis Scott. Dr. Scott checked himself into the hospital the previous day with heart symptoms, and he's just receiving a clean bill of health after spending all night on a heart monitor. But before Dr. Scott can leave, Monk notices something. The doctor has a bruise on his shin that looks suspiciously similar to the bruise Monk got from the coffee table in Dr. Whitcomb's office. Monk has a hunch that Dr. Scott somehow killed Dr. Whitcomb.
Lt. Disher makes some inquiries and learns that Dr. Scott had a motive. It turns out that Dr. Whitcomb was set to testify against Dr. Scott in an upcoming malpractice suit. The only problem is that Dr. Scott was hooked up to a heart monitor all night, and there are no extended breaks in his cardiogram. There seems to be no way Dr. Scott could have done it.
Later, while poking around on his own, Monk notices a water stain on the ceiling of Dr. Scott's old room. Following the stain, Monk makes his way through the closet, through the wall, and right into Hank Johansen's hospital room! It's not obvious because the two rooms are in different wards, but Dr. Scott's room and Hank Johansen's rooms are adjoining. And it's this little bit of information that helps Monk put everything together.
With Hank Johansen listening, Monk explains what happened. Late the previous night, Dr. Scott came through the closet while wearing his heart monitor. Dr. Scott took off his heart monitor and hooked it up to Hank so it maintained a constant readout. Dr. Scott then grabbed Hank's oxygen tank and shuffled down the hallway like an elderly patient, enabling him to get to Whitcomb's office without attracting any attention. Dr. Scott killed Dr. Whitcomb and calmly shuffled back to Hank's room, where he restored everything to its previous position.
Monk leaves Hank and takes off to find the previous night's cardiograms for Hank and Dr. Scott. If Monk's theory is correct, the two cardiograms should be exactly the same for the time Hank was hooked up to both monitors. Unfortunately, Hank thinks Monk is crazy and proceeds to telephone Dr. Scott to warn him. While Monk is searching through the hospital's records for the cardiograms, Dr. Scott attacks him from behind with a metal crutch. Monk is knocked out cold.
Monk wakes to find himself in a hospital bed, drugged and unable to move. Dr. Scott has arranged for an unwitting nurse to administer Monk a deadly dose of a drug that Monk is allergic to. Things couldn't look any worse for our detective. Just then, Natalie's conscience gets the better of her, and she decides to leave her date and head back to the hospital. She finds Monk just in time to prevent him from receiving the deadly dose of medication.
In the end, Dr. Scott is arrested, and Monk makes his way home after an extended stay in the hospital. It was a horrific experience for Monk, one that will likely keep him from hospitals for a long time. And it all began with a simple bloody nose.