The limo. They're leaving the city. Ted asks where they're going. "Vegas," Barney answers. Ted asks about the roof party. Barney says that a roof party is happening, but they're not going. Barney says that Ted's other friends want him to drink flat beer 10 feet above his apartment. "But not me, brah," Barney says. He's arranged for a private jet, the Valderrama suite at the Bellagio, steaks at Boa, Scotch at Ghostbar and then ringside seats to watch Floyd Mayweather go 10 rounds with... "Wait for it"... a grizzly bear! Holy shit! I want to be 30 again! Ted, annoyed, tells Barney to take him home. Barney says there's something he wants to tell Ted, but wanted him to be in the best frame of mind before he heard it. "You slept with Robin," Ted says flatly. The limo comes to a stop. Hey, Ranjit is the driver! Ranjit can't believe Barney slept with Ted's ex-girlfriend. He starts cursing Barney out in another language. Barney closes the window to shut out his own guilt. "When'd you find out?" Barney asks. Side-whoosh to the apartment. Right at the moment Marshall was about to open his soda can, Ted called for Robin. Ted is showing Robin an old photo of the two of them from a trip they took as Marshall opens the can and spills it all over himself. The photo Ted has is of a vacation they took to Vermont. Ted offers to let her kept he picture. "I slept with Barney!" she says suddenly. She says it was just one time, right after she got dumped by Simon. She says she was vulnerable and that she wanted to pretend it didn't happen, but she can't. That sounds a lot like she's blaming Barney for taking advantage, when that's really not what happened. Ted looks stunned. She asks if they're still friends. Let a brother think about it! Ted instantly says they're still friends. She asks if he's mad. Ted says he feels weird, but he's not mad. We side-whoosh back to the limo. "Wow," Barney says. "So you're not mad?" Barney asks. "No! I'm not mad!" Ted lies, in a high voice. Ted says that they broke up a year ago, he's with Stella now and he's fine with this. Barney says he's so relieved. Ted says offhandedly that his mom is coming into town next month. "MAYBE YOU'D LIKE TO NAIL HER, TOO!" he screams. Er, I guess he's a little mad.
Rooftop party. Goat petting. Lily asks if they can keep the goat. Marshall is not at all about that and would rather have his mental patient uncle come over if they want to live with someone who sheds and shits all over the place. Lily brings up that Robin slept with Barney and it's not very smooth. Marshall couldn't take the pressure anymore. Lily says that's so gross. Then she asks if it was amazing. Robin doesn't want to talk about it. Lily says she's curious because it's Barney and all. "Did he have devices and stuff?" she asks. "Hot wax? Did he tie you up?" Marshall and Robin are both shocked and Marshall asks what's wrong with her. "Was he all smooth down there?" Lily asks after a pause. OMG. With Lily next to the goat and everyone whispering, it's pretty funny.