Ned (Paul Rudd) is an idealist. His three sisters (Banks, Deschanel and Mortimer) are ambitious. Ned crashes at each of their homes, in succession, and brings truth, happiness and a sunny disposition into their lives. In other words, he wreaks havoc. Christian (Dancy), a pretentious painter friend of Natalie's (Deschanel) who tries to help Ned grow as a person by showing him another path; Hahn will play Janet, Ned's ex-girlfriend who, out of spite, is keeping him from reuniting with his beloved dog Willie Nelson. Knight will portray Ilene, Ned's overbearing and over-nurturing mother, who would be overjoyed if her son moved back home and; Montgomery will portray Arabella, a controversial British aristocrat that Miranda (Banks) is profiling for her magazine, a piece that could provide Miranda with the big break she has looking for.