Ted is faced with the possibility that he's the bad guy in the story of him and Zoey after spending time with the Captain. Barney wrestles with his feelings for Nora. Marshall won't throw one at Lily until he solves the world pollution crisis.
The gang are all involved in the same story, whereby Barney convinces Ted and Marshall to back GNB in the Arcadian battle which ultimately ends Ted and Zoey's relationship.
How I Met Your Podcast Ep 7.4 The Stinson Missile Crisis
Robin tells a therapist how the blossoming Barney/Nora relationship drove her to assault a stranger as Ted inserts himself into Marshall and Lily's pregnancy.