Oswald Chester is a resident at the Glorious Pines retirement community whose three-day disappearance has his friend Jervis Kent, a security guard at the home, worried. He went to the police, but they blew him off. The home's staff also didn't take him seriously, so he believes they're trying to cover it up and enlists Shawn and Gus to help him find Oswald. Our duo trick Henry into joining the team undercover as Talmadge McGulager, but he discovers something that Jervis had hidden from them: Oswald has disappeared from Glorious Pines twelve times before (and on the last three occasions had even received the warning that he would be kicked out if he ever did it again) only to show back up the next day. However, Jervis knows something is different this time as he could always tell beforehand when Oswald was getting restless and wanted to get away for a bit. Henry is annoyed and doesn't think this is worth their time, but Shawn and Gus notice that Oswald left without his wallet and prazosin, a high blood pressure medication. Shawn also finds the first clue as to where Oswald might have gone, as some of the days on his calendar have been marked with running distances and it's all leading up to the last day of the year: the Santa Barbara Marathon.
Shawn and Gus follow Oswald's likely trail and discover blood on a rock next to some steps. They also find a pedometer that accurately displays the distance between the steps and the home. They now know he must have fallen there somehow, but since his body is nowhere to be seen they go to the nearest hospital. They disguise themselves as hospital staff and eventually find Oswald because Shawn recognises a tattoo from a picture taken during his younger years that he had seen in his room at Glorious Pines. The two medical residents in Oswald's room, Walker and Ramachandran, explain that he's in a coma, was "admitted two days ago with severe hypotension causing low brain perfusion" and also "suffered intracranial bleed from syncope and falling down." In other words, "his blood pressure went boom and his brain got an owie." They also noticed that his blood pressure didn't immediately rise when they administered fluids, which they conclude probably means that he accidentally took too much of his prazosin before he went running.
Our duo go back to the home to tell Henry that they solved the case, but he is convinced there's more to it than meets the eye and says they should keep investigating at Glorious Pines. Shawn and Gus think he's simply stalling because he likes getting pampered at the home, but just then two other residents fall ill. These are Sam and Harley, and Shawn and Henry have both noticed they were wearing the same bracelet they had earlier seen in Oswald's room.
At the station Gus shares his theory that they could be dealing with an "angel of death" scenario, but Lassiter and Juliet believe it's more likely that all three residents simply fainted as a result of the current heat wave. Jervis tries to get the police to finally start a proper investigation, but he's again not taken seriously. Juliet says that none of the doctors treating the patients suspect foul play, but Shawn mentions the bracelet connection and convinces Karen to let them keep investigating.
Back at Glorious Pines, Jervis informs Shawn and Gus that Chelsea makes the bracelets in craft class and "doesn't just give 'em to anybody." Our duo then see her tangoing with Henry, and Shawn cuts in twice as he and Henry alternate dancing with her while asking her about the case. She tells them that Oswald and Harley are two ex-boyfriends whom she met at the "heart-smart high blood pressure seminar" that she hosts.
They think the case through one more time, and when Henry suddenly remembers that someone had recently stolen blood pressure medication out of the on-site pharmacy their suspicion of foul play only grows. Shawn and Gus sneak into chief administrator Pamela's office in hopes of finding a list of residents on this medication so that they can identify potential targets, but instead they discover information that solves the case on the spot: a waiting list to get into the home with Rhonda Cloverfield, mother of the Meredith Cloverfield in charge of room service, in seventh place. Meredith wanted to bump her mother up the list to get her out of the terrible Sunshine Meadows home as soon as possible and knew that Glorious Pines does not provide full-time medical care, so she stole the medication and slipped it into the food of the three victims to ensure they would overdose and get kicked out of the home after forever losing their good health. She knew they were already on the medication thanks to the friendship bracelets the uninvolved Chelsea would give those who attended her seminar. Meredith is arrested and later makes a full confession.
