Lily and Marshall have trouble finding a nanny within their budget until they meet Julie, who declines their offer and explains that she is running off to Paris to be with a billionaire single father she just met. Lily and Marshall figure out that Barney is her suitor and when they confront him, he explains his elaborate scheme to pose as a single father to meet sympathetic nannies. Lily's dad Mickey proves that he can be a good babysitter when he takes care of Marvin in Marshall and Lily's absence and they agree to let him be their new nanny. Robin and Ted butt heads over who has a more serious relationship until each breaks down and admits the shortcomings of their significant other.