It's weeks before Barney and Robin's wedding, and one of the many things they still have to decide is where to live. The one thing Robin insists is that they don't live at Barney's apartment. So it goes on the market. However, Barney doesn't want to sell it to just anyone, but someone who is worthy of what was and will always be in his heart his "Fortress of Barnitude". Robin has a slightly different idea, which isn't as easy to achieve as she would like when she and others learn more and more about with what Barney has equipped his apartment. Meanwhile, Lily hasn't spent much time of late with her family because of her job with The Captain. She seems to be at his beck and call, and doesn't seem to mind. Marshall understands, until it affects a planned evening out. So, Marshall decides to cheat on Lily with someone who Lily knows.