Usually cold-hearted Robin is in tears over the news that her mother will not be attending the wedding. In trying to make Robin feel better, Ted, Barney and Lily each are brought back in their memory to a time six months earlier. Then, Lily noticed that the challenges that Barney always accepted in picking up women were those that he issued for himself. So Lily and Robin went on a quest to issue Barney challenges on picking up women that they believed he could not complete. This quest became an all night task. The one challenge that Barney felt like no challenge at all ended up being the most difficult not so much for the challenge itself, but for the advice he got in return. What Robin, Barney and Lily are and were unaware of is that at that same time, Marshall tried to convince Ted that, based on inside information, he should still try to pursue Robin, despite Ted vowing that their relationship was then purely platonic. Events, including a telephone call from Chicago, made Ted truly.