Barney tries to make his life seem more exciting as he bonds with his father (John Lithgow); Robin encounters a guy she likes.
The gang recognizes similarities between their significant other and their parents; a string of unfortunate events ruin Nora and Barney's evening of romance.
When the gang helps Barney's mother move, they learn that she has lied to him about events throughout his life; Robin oversells Ted to a blind date.
The team hunts a suspect who impregnates young women, has them give birth and murders them.