Madeline and Shawn bring Henry back from the hospital. Madeline says she can only stay a couple days and that it is her wish that Shawn take care of Henry after she leaves.
Later that day, after realizing the lease on his apartment is up soon, Shawn comes up with a plan to move in with his father to help take care of him until he is better. When Shawn tells Juliet this news, she is disappointed because she thought maybe Shawn would move in with her when his lease was up.
Meanwhile, Gus has set up a dating profile on an Internet dating website called SoulMateConnection.com. Shawn makes fun of him for it, but Gus remains proud because he has scored a date with Rachael, a beautiful Indian woman. While Gus is searching the site's database, he is shocked when he comes across a profile belonging to Juliet -- but she isn't calling herself "Juliet"; she's claiming to be a woman named "Helene." Gus reluctantly shows Shawn the profile, but Shawn plays it off cool; Juliet would never be unfaithful.
But Shawn can't help but be curious, so he heads to a restaurant where Juliet is having dinner at that night. To Shawn's surprise, he sees that Juliet is actually on a date with another guy. Shawn immediately interrupts the date and tells Juliet's date Mike that he's her boyfriend. But Juliet tells Mike that Shawn is her ex-boyfriend. Shawn is mystified by this entire situation. We then cut to an area of the restaurant where Lassiter has a surveillance table set up. Juliet is on a date with this guy Mike because she's actually undercover on a case, and Shawn is about to blow the whole operation. Lassiter orders McNab, who is playing a waiter undercover, to retrieve Shawn. When McNab approaches Shawn, Shawn figures it out; Juliet isn't on a date with this Mike guy -- she's undercover. Shawn feels a sense of relief.
Back at the SBPD, Vick briefs the team on the progress of the undercover mission Juliet is involved in. She tells them that in the past three months, two women have been murdered by strangulation and that both were found in dense, wooded areas. She then reveals that the two women both had profiles on SoulMateConnection.com and had dated a cross-section of the same six men. Vick believes that their killer is one of them, so she explains to the group that Juliet has been going on dates with each of these men in hopes of finding out which one is the killer. But after weeks of not finding their guy, Vick suggests that Shawn join the case to get a psychic read on of the remaining suspects.
Later, Shawn meets Gus's date Rachael. They don't exactly hit it off, but Gus is already smitten with her and the chemistry between the two of them is undeniable. Shawn isn't so sure about it though.
Meanwhile at Henry's house, Madeline informs Shawn that she is going to be staying a little longer than she expected. Shawn is less than pleased by this news; he's now a man in his 30s living with his parents.
That night, Shawn and Lassiter are in the surveillance van outside the movie theater watching Juliet go undercover on a date with an attractive guy named Lordon. The mission is suddenly threatened when Gus shows up on a date with Rachael. Shawn forgot to tell Gus that Juliet's dating profile on SoulMateConnection.com isn't real, and that it's actually part of her cover for a mission she's heading up.
Gus is not okay with Juliet being on a date with another guy. Back in the surveillance van, Lassiter is freaking out; he knows that Gus could blow Juliet's cover if he starts to make a scene. But Gus, being the mature gentleman he is, keeps his composure and continues his date with Rachael. After the movie, Lordon walks Juliet to her car and tells her he has a surprise for her. He asks her to turn around and close her eyes. Juliet is slightly alarmed, and Shawn and Lassiter are too. They think that Lordon is about to strangle Juliet like the rest of his victims, so they rush out of the van and head in the direction of Juliet. But it was only a false alarm; Lordon had bought Juliet a necklace and he was simply going to place it around her neck as a surprise. From this, they decide to cross Lordon off their list of suspects.
The next day at the SBPD, Juliet, Vick and Shawn are speaking with Mellish, a technical rep from SoulMateConnection.com who's been tracking their suspects' correspondence on the site. Juliet has been trying to get a date with the next suspect on the list, an extremely attractive, renaissance man that goes by the name of "Mr. Possibilities." This guy is basically the hottest catch on the website; he's picky and in constant high demand for dates. Mellish tells Juliet that if she wants to get this guy's attention, she needs to spruce up her dating profile. She agrees, and she and Shawn head to a clothing store to get some sexier attire to attract Mr. Possibilities.
While at the clothing store, Juliet runs into Lordon. He's very happy to see her and wonders if she received the flowers he sent her. This guy is obviously into her, and Juliet is enjoying watching Shawn be jealous. Lordon asks Juliet out on another date, but Juliet politely declines.
Shawn then has a light bulb moment. He heads back to the SBPD and points out to Mellish that they've been concentrating solely on the men these dead women dated; instead he suggests they investigate the women that Mr. Possibilities rejected. Maybe the killer isn't a man; maybe the killer is a woman who was so jealous of the women that Mr. Possibilities did choose to date, that she killed them because of it. Mellish then pulls up a long list of correspondence and finally comes across a woman who has contacted him many times and has gotten rejected by him more than any other woman on the site. To Shawn's surprise, this woman is Rachael, Gus' new girlfriend.
Shawn heads to the mini golf course where Gus and Rachael are out on a date. Shawn immediately accuses her of being the murderer the SBPD has been searching for. Gus is shocked. But Rachael quickly trumps Shawn's accusation by presenting her alibi: a time stamped photograph of herself giving a speech in New York. She's not their killer, and Gus is offended that Shawn would even suggest it. Just then, Shawn gets a call from Juliet saying she finally scored a date with Mr. Possibilities and that she needs Shawn to be in the surveillance van for it.
Meanwhile back at Henry's, Shawn is mortified when he walks in on his parents making love. At this point, Shawn is at an all-time low: his girlfriend is going on a date with another guy who is basically the definition of perfect, his best friend has a new girlfriend he doesn't get along with, he lives with his parents and a killer is still on the loose.
Later that night, Shawn notices a picture of Mr. Possibilities in a clothing ad. He finds this to be odd, so he pulls up Mr. Possibilities' dating profile to compare the pictures, and sure enough, it appears that Mr. Possibilities photoshopped pictures from a clothing catalogue of a male model into different backgrounds and used them as his profile pictures.
Shawn recruits Gus to investigate who this Mr. Possibilities guy really is. They head to his house and discover that his real name is Ken Dowling and that he has a wife and a family. Shawn and Gus enter the house and break the news to the Ken's wife that he's been cheating on her and that he's wanted for the murder of two women. Ken insists that he's innocent and that he didn't create that profile; he claims that someone else who had access to those pictures must have done it. But Shawn's not buying Ken's story, so he alerts the SBPD and they have him arrested. Shawn calls Juliet to tell her that they caught Mr. Possibilities and that she no longer needs to go out on a date with him that night undercover. Just as the squad car is about to take Ken away, Shawn gets a call from Mellish saying that Mr. Possibilities sent an email ten minutes ago -- which means that Ken, the guy they just arrested, isn't the murderer. Mr. Possibilities is still out there and they have no idea what his real identity is or what he even looks like.
Later that day, at the date location she was supposed to meet Mr. Possibilities at, Juliet gets a visit from Mike -- the first guy we saw her out on a date with. He asks Juliet if she's waiting for her date with Mr. Possibilities. But before she can say anything, Mike informs her that Mr. Possibilities doesn't exist and that he was the one who created his profile. When Juliet asks Mike why he did this, he tells her he did it to prove a point - that women are lying when they say all they want is a nice guy and that looks and money don't matter. Knowing that Juliet was one of the women that rejected Mike and tried to go after Mr. Possibilities (like the two murdered women), he pulls a gun on her and tells her she is going to pay for it , like the other women he killed.
Shawn knows that Juliet's life could be in danger since Mr. Possibilities is still out there, so he grabs Lassiter and the SBPD and they race to save her. But Juliet is smart and she knows how to handle a situation like this. She starts to pretend to be attracted to Mike and tells him that she understands why he would kill those women. Mike starts to soften, Juliet leans in for a kiss then immediately takes the opportunity to knock him down and grab hold of his gun. Just then, Shawn and the SBPD run up and see that Juliet has already taken down their killer. They arrest Mike and Juliet is rewarded for her bravery.
Later that day, Shawn tells Juliet that he's had a revelation: that he's ready to move in with her. Juliet asks if he's sure, and Shawn reassures her that he's never been more sure of anything in his life... especially after he walked in on his parents "doing it."
Back at the Psych office, Gus and Rachael decide they want to continue to date exclusively. But before Rachael can fully commit, she has a secret to reveal to Gus... she has a son named Maximus. Maximus comes running in to meet Gus, but Gus is too shocked for words.