The episode begins with Holmes trying to choke a man. Well, it is a dead body and he is practicing his choke hold. Also this is a part of his experiments that are crucial for his investigation purposes. These people have donated their bodies to science and since the attendant owes Holmes a favor, he was let inside the morgue. Watson however isn’t too comfortable. They are on their way out and Holmes thanks Bruce for his help. Just then a new body is brought in. This man died an hour ago, and he died of a heart attack. Watson takes a look at the body and states that the old man had brain cancer as there is a mark suggesting that he was under radiotherapy.
Watson thinks that the heart attack was triggered due to his ailment but Holmes isn’t in agreement with that. He then heads to the room where the old man was kept. He tells Watson that the dead man was given epinephrine and that was the COD. But Watson says that it is a common drug given during all cardiac codes. He reaches the room and asks the janitor to leave. He then shows a mark on the dead man’s finger and Watson identifies it to be eskemia caused due to epinephrine. But if e had been given epinephrine during the code, that is after the heart had stopped, it wouldn’t have caused eskemia. So, they are investigating a murder. The hospital guards knock at the door. But Holmes doesn’t let them in as it would ruin the crime scene.
He wonders how the killer escaped after giving epinephrine to the old man and before the onset of a heart attack, as the nurse said there was no one in the room. Watson deduces that the killer must have injected it into the IV, which could give him ten minutes. And also the pump is turned down. He then checks the waste bin. Next, Watson sees an old doctor friend, Carrie Dwyer and introduces her to Holmes. Gregson is talking to the administrator, Richard Sanchez. Gregson asks Holmes to apologize to Sanchez after which, they will be given full access to the crime scene. Holmes is furious that he had to apologize to Sanchez. He says that they need to find the woman who brought coffee for the victim as he saw two coffee cups and one of them had lipstick marks. He then shows Watson a receipt from the coffee shop and points out the name and number of a guy named Dave.
He knows that Dave was flirting with the woman as he gave her more than she ordered. Dave remembers that the customer was a sexy blonde doctor. But Homes figures out that the woman wasn’t a doctor as a doctor would never wear heavy perfume or tight fitting clothes. Watson thinks she knows where they could find Dave’s sexy doctor. She takes Holmes to a high end cosmetic store. They find a blonde there who matches Dave’s description. She is surprised to hear Trent Kelty is dead. They were neighbors and she felt sorry for him when he completely lost his sight. That is when she started visiting Trent more often. But according to the timeline Holmes thinks that she cannot be the killer as she left an hour before the murder took place. She says that Trent had no friends or family.
The only person he spoke was the doctor who visited him every night and he was helping him cope with the pain. Holmes remembers a cut up pancake on the table and Jacqueline says that she didn’t cut it up for him. Holmes knows that the person who cut the pancake is the killer. Holmes then proposes his theory in which he thinks that killer had cut the pancake into child like pieces which means he likes the dependence that his victims show towards him. Also, he chooses weak and sick people who are doomed to death. The hospital provides an endless supply of the same. They then meet the Head of Surgery and they know he hates Sanchez. They want him to grant access to all medical records of the earlier deaths in the hospital. Dr. Baldwin agrees. Holmes lists down 73 deaths due to cardiac events.
Watson knows that the drug used to kill is hard to get hold of and so she checks different logs and finds out that epinephrine went missing on 9 occasions which corresponds to the dates of 9 deaths. So the killer has killed 9 people. They have their pattern; so now they can start listing their suspects and there are 23 of them. Holmes then decides to check the charts and find out who was on duty on those nine days and who didn’t have access to the floor. He suggests that they could be looking at nurses as Trent was blind, so he would never know the difference. In the elevator, Holmes apologizes to the janitor for his earlier behavior. Holmes goes to his first suspect, Dr. Baldwin.
But he says that he is too indifferent to his patient’s pain to be the Angel of Death and since the angel’s act is that of mercy, he couldn’t be the killer. Holmes agrees with him and he has an alibi as he was on a train during Trent’s death. Watson is with Carrie and she tells her about the situation. Carrie finds it weird. She then takes Watson along to meet one of her patents, Morgan who tore her ACL during a soccer match. Watson notices a mark on Morgan’s left toe. Holmes and Bell interview another doctor, Cahill and Holmes thinks that he isn’t their angel. Bell thinks otherwise but moves on to their next suspect. Watson tells Carrie that Morgan might be suffering from endocartitis but Carrie dismisses that option. Carrie then agrees to do an echocardiogram.
On their way back, Watson gets a message saying that the ECG was normal. Holmes tells her that she should trust her first instincts. He then notices Cahill’s car and finds it weird that it is still there as Cahill had said that he was about to leave for home after a 29 hour shift. Then why is he still in the hospital? We see that Cahill goes into one of the patient’s room with a syringe and the cops get hold of him Watson points out that the syringe is empty and that he was trying to steal morphine from the patient. At home, Watson sees that one of the patient’s that was killed was not terminally sick; she was recovering after surgery. So why did the Angel make an exception with her? Gregson calls and tells Holmes that Cahill is peaking. Cahill tells Holmes that once he was stealing from a patient and then hid in the bathroom to take the drug.
As he was about to leave, he heard a voice talking to the patient about his cancer; he sounded like a doctor but Cahill didn’t see his face. Watson tries to convince Carrie to perform another test on Morgan but she tells Watson to back off. Holmes has a breakthrough in the case. He identifies that one of the 9 victims was a Ukrainian and that since the Angel spoke to his victims before killing them, he should have known Ukrainian. But none of the doctors know it. But also, it isn’t necessary that all doctors remain doctors! We then see that Holmes and Gregson are interrogating the janitor. He was a doctor in Ukraine Gregson pulls out a log of medical notes about the 9 dead patients from the janitor’s house while he was at the hospital.
Gregson says that he “freed’ them from their pain. Holmes then asks about Samantha and the janitor says that she was dying. Holmes argues that she was recovering but the janitor tells him that he is like the police who build lies to suit their truths. Holmes is now disturbed as to why was the Angel so convinced that he was right about Samantha’s condition. Carrie arrives home and tells Watson that she was right about Morgan and that someone had put in an anonymous note in Morgan’s chart for a TEE test. This gives Holmes an idea. Next, Gregson and Holmes talk to Baldwin. Holmes says that Baldwin was brilliant as he had figured out that about the Angel a while back. So, when he made a surgical error by leaving a clamp in Samantha’s chest, he knew that the Angel would kill her due to the tremendous pain she was going through.
He could have done another surgery, but that would be a third strike on his already tainted career chart. Holmes knows that Baldwin found a patient suffering from chest cancer and put Samantha’s name on those results. And all he had to do was to put Samantha in pain and that made her too delirious to talk. The Angel took the bait. They tell Baldwin that they exhumed Samantha’s body and found the surgical clamp. Holmes also has proof that he faked the results as the Angel told Holmes about the pictures he had taken about the medical reports and Samantha’s reports had Baldwin’s signature on it. at home, Holmes acknowledges the fact that Watson is a great doctor. Watson deletes all the pictures of her medicine days. The episode ends.