While the girls are in Las Vegas drinking and carousing, the boys are playing "Dungeons & Dragons". The weekend doesn't turn out quite the way each group expects. The boys are down one when Raj receives a text from Lucy to hang out with her, which he does. Although their date doesn't go quite the way Raj would have wanted, their shared fear may instead bring them closer together. And out of circumstance, the girls are turned away at the airport and thus never make it to Vegas. As they seem to have nothing else to do, Leonard invites them to stay to play D&D with them. While Howard relishes his role as dungeon master, and as Sheldon relishes watching Howard in his role as dungeon master, the girls end up adding their own sensibility to the game. Penny in particular uses it for what she believes is Amy's advantage.. or is it?