The film portrays the lives of shy conjoined twins Blake and Francis Falls, who take residence in a rundown hotel to hopefully reunite with their estranged birth mother.

They agree to attend a Halloween party with Penny and pretend to be wearing a "Siamese Twins" costume.

"[3] He added, "We can imagine [the brothers’] lifetime of isolation from the normal things people do", and concluded "In its quiet, dark, claustrophobic way, this is one of the best films of the year.

"[3] Janet Maslin of The New York Times said, "It's a film that dwells as hauntingly on loneliness as it does on never actually being able to be alone", and that Mark Polish gives an "especially affecting performance.”[4] At the 1999 Deauville American Film Festival, Twin Falls Idaho was honored with the CinéLive Award, the Fun Radio Trophy, and the Jury Special Prize (tied with Sarah Polley’s Guinevere).

[7] The film received a Special Recognition notice from the National Board of Review for excellence in filmmaking.