The Unexpected Man, Apple Tree Theatre. This new play by Yasmina Reza, who also wrote Art, is so slight that if not anchored by substantial performances it will simply float away. Fortunately, William Brown and Peggy Roeder as its two characters–a midlist author and his biggest fan, who happen to share a train compartment–touchingly reveal all the ways we project our fantasies and hopes onto other people. While the unnamed man frets over minutiae–his daughter’s much older boyfriend, others’ reservations about his new book, his digestion–the woman engages in an imaginary conversation with him about the meaning of life as expressed in that book, which she doesn’t quite have the nerve to read in the author’s elevated presence. Director Ross Lehman manages to keep the evening from feeling static despite its challenging format–alternating monologues in a confined space–and the actors give funny, thoughtful readings of Reza’s droll observations about aging, loneliness, and loss.