Shawn and Gus are hanging out in the Psych office when Henry pays a visit. He criticizes everything about the place until Shawn stops him. They are waiting for an appointment. Henry says he is their appointment. A friend of his, Bill Peterson, called him and said he thinks his son Brandon is mixed up in something bad. He doesn't want to call the police and Henry inadvertently made him think Shawn could help. Henry leaves just as Peterson arrives. He tells them that Brandon used to work for him but he fired him in an attempt at tough love. He's been evicted from his apartment, had his cell phone turned off and forged a check of Peterson's for thirty thousand dollars. Now's he's missing. Shawn and Gus, deliberately against Henry's wishes, say they can help.
At the police station, Juliet approaches Chief Vick about throwing a surprise party for Lassiter's birthday. Vick tells Juliet that Lassiter doesn't like surprises and advises her against it, but Juliet decides to proceed anyway.
Shawn and Gus go to Brandon's apartment building. If he was evicted, his landlord is probably holding his stuff for ransom in storage until Brandon resurfaces to pay his bill. In the storage compartment, they find a stack of unpaid bills, indicating cash flow problems, and a business card for a lawn and garden store, a strange thing to have when one lives in an apartment. On the back of the card is written "RRLRLL."
At Garden Works, Shawn and Gus notice cars way to expensive to be putting plants in. They decide to follow a guy who gets out of a Ferrari and disappears behind the building. On the way, Shawn notices the hand of a woman hanging out of a car with a bracelet with a distinctive charm on it. When they get behind the building, they encounter a hedge maze. Shawn figures out that "RRLRLL" is the key to the maze. When they get through it, they discover a high stakes underground poker game run by a guy named J.P. Berger. Gus says he's a whiz at online poker and he can use those skills to get in and get information. But before they enter, they see Berger about to cut someone's finger off with pruning shears. Shawn and Gus quickly take off.
Back at the Psych office, Shawn has a psychic episode in front of Peterson and Henry, who can barely contain his disdain. Shawn tells them that Brandon has been playing poker and asks if Peterson heard Brandon mention any names. He says Brandon played online and his screen name was 'DumbLuck2'.
Later, Gus is playing online poker and tells Shawn he's played against 'DumbLuck2' before, and he's playing now waiting for Brandon to sign on. As Gus plays, Shawn, without looking at the screen, can tell exactly what cards Gus has just by his tells. Finally, Brandon logs on and Shawn pretends to be a girl interested in a date to lure Brandon out of hiding.
They meet Brandon at a coffee shop when suddenly Berger shows up, roughs up Brandon and tells him he has until Monday to get him his money. Brandon tells Shawn and Gus that he lost everything he stole from his dad and more to Berger. He can't go back until he wins it back. He's actually a really good player and can't figure out how he keeps losing to Berger. Shawn advises him to go back to his dad and together figure out a way to pay Berger back. It's that or jail. Peterson's done enabling him. Brandon agrees, and he takes off his lucky charm necklace as the guys drop him off at his dad's car lot.
Meanwhile, Juliet has been sneaking around trying to plan Lassiter's party. She finds an address book in his desk and is happy to have a guest list.
Henry summons Shawn to the car lot at the crack of dawn the next morning. It turns out Brandon waited until his father went home, sneaked in, opened the safe and stole a sack full of cash.
Shawn, thinking Brandon must be a great poker player with that bluff he just pulled on them, reviews the surveillance tape of Brandon's robbery with Gus. He notices the lucky charm back around Brandon's neck and figures he's gone to play Berger again. Gus says there's only one place Berger will be this weekend - the World Poker Derby. They grab Henry and Peterson and head to the casino. They find Brandon but it's too late. He's already paid his entrance fee and there are no refunds. Shawn decides to play in his place and manages to psych people out all the way to the finals with Berger, where he notices the dealer is wearing the same bracelet he saw at Garden Works. He figures out that Berger and the dealer have been working together, cheating. That's why Brandon kept losing. He discovers the cards are marked and security guards come and haul Berger and the dealer away. Shawn gives his winnings to Peterson, who hands Shawn a bundle of cash for his services, and heads out with Brandon, on the way to healing their broken relationship. With cash in hand, Gus has dreams of an office upgrade but Shawn proceeds to lose it all on one turn of the roulette wheel.
At Lassiter's house, Shawn, Gus and Juliet wait with some shady-looking characters for the birthday boy to show up for his surprise party. The real surprise, it turns out, is that all the guests are former collars of Lassiter's, who keeps their addresses on file to keep tabs on them. With them all now knowing where he lives, he goes inside to pack.
- The title is the punchline to an old and possibly partially-forgotten piece of ribaldry, and a play on the words 'poker' and 'poke 'er'.
- The no name brand potato chips in the Psych office are only sold in Canada.
Berger: If you were psychic, I wouldn't be cleaning your clock right now!
Shawn: Cleaning my clock? What does that mean, Berger? What, you'd take time out of your day to clean another man's timepiece, and if so, that would be a bad thing? No, I would be gracious, I would say, "J.P., dude, thanks for spritzing my watch!"
The gallery for Poker? I Barely Know Her can be found here.