After Marshall witnesses a work buddy get yelled at after handing in a report, he becomes paranoid that the same will happen to him.

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...

When Zoey enrolls in Ted's class, she manipulates his students into taking her side in the fight to save the building being torn down to make room for his project. Meanwhile, Marshall and Lily spot Robin marching in the Halloween parade of shame.

When the gang goes to a black tie event at the Natural History Museum, Ted gets introduced to Zoey's husband, The Captain.

Marshall becomes obsessed with saving the environment after seeing a documentary on garbage. Ted runs into The Captain. Barney admits he has feelings for a woman.

When Marshall and Barney argue over the destruction of the Arcadian Hotel, Robin and Lily try to mix the right combination of cocktails that will force them to make up. Meanwhile, Ted plans a romantic weekend away with Zoey.

When Ted is faced with an important decision that might affect his future with Zoey, the gang expresses their true feelings about her.

Robin and Barney bond when they intervene in Ted's relationship, and Marshall and Lily watch a ticking clock as he fears that he soon will be the victim of food poisoning.

When Barney designs an extensive pre-nup, the guys take note and propose their own relationship amendments to their significant others. Meanwhile, Quinn is outraged and draws up a pre-nup of her own, which causes friction between the sexes.