Charlie Sitter (CHRIS WEITZ) is a successful recording industry executive who's just received a note from someone he hasn't heard from in years. It's from Buck O'Brien (MIKE WHITE), a 27-year-old simpleton whose mother had just died after a long illness. Although he hasn't seen Buck in sixteen some years, he and his live-in fiancée, Carlyn (BETH COLT), fly across the country to attend the funeral.
There, Carlyn learns that Buck and "Chuck" were once close childhood friends, and Buck seems to be a sweet natured, but lonely man. As such, she and Charlie invite him to visit them sometime in Los Angeles. Charlie, however, begins to think that was a mistake when Buck comes on to him sexually in a bathroom during the wake.
Despite Charlie then essentially closing any possibility of Buck visiting them, the persistent young man packs up his belongings - mostly childhood toys and mementos - and moves to L.A. Once there and setting up home in a motel, Buck starts stalking Charlie at home and at work, finally building up the courage to approach him once again.
Not surprisingly, Charlie isn't thrilled to see Buck or learn that he's moved close-by and wants to rekindle their close friendship. Despite Charlie giving him the cold shoulder, Buck continues with his efforts that include patiently waiting outside a children's theater playhouse across the street from Charlie's office.
There, he eventually meets Beverly (LUPE ONTIVEROS), the house manager, and after reading a script for "The Wizard of Oz," has an epiphany. He'll write a theatrical version of his previous and current relationship with Charlie, call it "Hank & Frank," and use it to show Charlie how he feels. Hiring Beverly to manage and direct the one-night production and untalented actor Sam (PAUL WEITZ) to play the part of Chuck, Buck hopes that his efforts will rekindle their friendship.
As the days count down to the play and Charlie and Carlyn try to get on with their lives despite Buck's persistent and growing obsession with Chuck, it's only a matter of time before things come to a head with big revelations about their past surfacing that cause the two men to ponder their past and future relationship together.