Eleanor, Michael, Janet and Tahani have their hands full when the new residents begin to show their true colors. Jason receives some unsettling news.

With Eleanor assuming the role of the architect, the group adapts to the challenges facing them when four test subjects inhabit a new neighborhood under their supervision.

Dennis, Mac, and Frank go into real estate, while Dee sets out to be a surrogate for a wealthy couple. Charlie gets into it with an attorney over the law.

Marshall and Lily make a secret pact to start trying to have a baby if they ever finally see Barney’s doppelganger. Meanwhile, Robin finally gets an offer for her dream…

When Ted and Barney jeopardize Robin’s new relationship by professing their love for her, Robin realizes that she is finally over them. Meanwhile, after spending a weekend sleeping in twin…

When Robin confesses that she is still angry with Barney for the way he handled their break-up, she enlists the help of Anita, a self-help author who plans to beat…

When Lily and Marshall forget to fix up Ted on a blind date for Valentine’s Day, they use one of Barney’s many discarded girls to see if they may become…

When Marshall picks up smoking again, it prompts Lily, Ted and Barney, ex-smokers all, to succumb as well. Meanwhile, Robin gets a new co-anchor at her show…