The Robin is a play and the secret final page of Barney's Playbook.
In Platonish, Barney inadvertently meets the Mother when trying to complete one of Lily and Robin's many challenges and gets shut down by her, when he tries to get her to sleep with him. The Mother, however, helps him realise that he is still in love with Robin so he goes back to his apartment and creates the Robin.
The first step is carried out in Splitsville, where Barney admits to Robin, in front of her then-current boyfriend Nick, that he is completely in love with her. This leads to Nick and Robin breaking up, and later on Barney plays it off as a fake romantic speech.
The third step is put into action in Twelve Horny Women, where he tells Robin that he is done trying to get her back. As he leaves the booth to get them some drinks, Robin looks unsure if that is what she wants. Later, Barney is looking at her trying to gauge her reaction.
The fourth step is all the events that happen in Lobster Crawl, where Robin does a list of plays to win Barney's affections for just one night. He turns down all of her advances, which makes her crazy enough to show up at his doorstep in purple lingerie.
The fifth step we're led to believe, is when Barney notices Robin screaming at Patrice in Lobster Crawl. After he sends away Brandi, he explains to Patrice about his play and his outcome of it and asks her for her help. She happily accepts as she loves Robin.
The sixth step comes directly after Patrice, as she gives him a huge bear hug and we can hear his spine crack.
Step seven comes at the end of Lobster Crawl, when Robin shows up at his doorstep in lingerie, inviting him to have a one night stand with her. He turns her down and gestures over to Patrice, who's sitting on his couch. He tells Robin that he and Patrice are on a date.
Step eight is when Robin breaks into Barney's apartment in The Over-Correction, to seek Barney's playbook. She believes the playbook will put an end to Barney and Patrice's relationship. After a few attempts, she finally finds it, but Barney coming back into the apartment, forces her to hide in his closet of suits. Unbeknownst to Robin, Barney is at Maclaren's the entire time, watching her on his phone. He dials Patrice to tell her that "The Robin is in the nest... that means Robin broke into my apartment".
Step nine happens in The Over-Correction as well. When Patrice comes into the apartment and Barney asks her to get his laptop, Robin sets The Playbook on Barney's bed. Patrice discovers the book and questions Barney about it. Robin expects him to lie his way out of it, but Barney astonishes her by admitting the truth to Patrice about his womanizing past. Patrice rushes out to the balcony making Barney join her and they stage a fight, but in reality, he's thanking her for all her help.
Step ten still happens in The Over-Correction when Robin, Ted, and Lily are hiding in the kitchen pantry. Barney and Patrice end their fake fight and come back inside the house. Patrice tells him that she can't date a man who has a playbook. Barney says he understands and then grabs his playbook and throws it in the trashcan. He then lights a match and throws it in there, burning his playbook. It's later revealed however, that was only the ceremonial playbook, the actual playbook existed until Weekend at Barney's.
Step eleven is the last piece of The Over-Correction, where Robin convinces the gang to have an intervention for Barney, who she believes has lost his mind. They agree, but in the end, actually hold it for her as they believe she's gone crazy over losing Barney to Patrice. Barney monitors the gang's intervention for Robin via hidden cameras he has in Lily and Marshall's apartment.
Step twelve takes place in The Final Page - Part One. Barney is jinxed and to break this jinx, he reveals to Ted a diamond ring. Barney explains to him that he's going to propose to Patrice on top on the WWN building on the night of Ted's GNB building opening. He makes Ted promise he won't try to talk him out of it and two, he can't tell anybody. Ted agrees, but has trouble keeping the secret from Robin.
Step thirteen is when Ted finally tells Robin in the limo that Barney is getting engaged in The Final Page - Part Two. Ted urges Robin to go after Barney as she's still in love with him. Robin tells him she's done going after Barney and that she would much rather go to his party. Ted has Ranjit stop at the WWN building and finally, convinces Robin to stop Barney from proposing to Patrice. Barney's voice over later in the episode tells this is the point where Ted has let go of Robin, and has given Barney his blessing.
Steps fourteen through sixteen all occur on top of the WWN building. Robin discovers "The Robin" play and voice over from Barney confirms that this will be the last play he ever runs.
Step fifteen is when Robin notices the mistletoe above her head, which signals Barney to step out of his hiding place and listen to her scolding of him manipulating her.
After Robin is done yelling at him, Barney tells her to turn the page over. Robin angrily flips the page over and reads step 16. She looks at Barney who's down on one knee and he asks her to marry him. After a few seconds of silence, Robin finally says yes.
- Step 1: Admit to yourself that you still have feelings for this girl.
- Step 2: Choose the completely wrong moment to make a drunken move after hanging out at a strip club… and get shot down on purpose.
- Step 3: Agree that you two don’t work, locking the door on any future you could have together, which will drive Robin nuts.
- Step 4: Robin goes nuts.
- Step 5: Find the person who annoys Robin most in the world and ask for her help. Explain everything to Patrice and hope she agrees to help.
- Step 6: Check with your doctor about possible broken ribs.
- Step 7: Pretend to be dating Patrice.
- Step 8:Wait until Robin inevitably breaks into your place to find The Playbook and show it to Patrice, which you’ll monitor via the hidden cameras you have in your apartment.
- Step 9: After Patrice “finds” The Playbook, have your first “big fight.”
- Step 10: Prove your loyalty to Patrice by burning The Playbook, and actually burn it. You don’t need it anymore.
- Step 11: Because your friends have no boundaries, they’ll inevitably have an intervention for Robin, which you’ll monitor via the hidden cameras you have in Marshall and Lily’s apartment.
- Step 12: Tell only Ted about your plan to propose to Patrice.
- Step 13: Wait and see if Ted tells Robin. And if he does, it means your best bro in the world has let go of Robin and has given you his blessing.
- Step 14: Robin arrives at her favorite spot in the city and finds the secret final page of The Playbook… the last play you’ll ever run.
- Step 15: Robin realizes she’s standing underneath mistletoe.
- Step 16: Hope she says yes.