The film begins in mid-stride. A cabbie and a passenger are coming to some sort of arrangement, and in a deft bit of exposition by screenwriters Ramin Bahrani (who also directs) and Bahareh Azimi, the plot is laid out: an old man (Red West) wants to be driven from the city of Winston-Salem, North Carolina to a place called Blowing Rock, about two hours away. The cabbie (Souleymane Sy Savane), is happy to receive the fee, but since West doesn't want a return trip he's concerned the old man is going to jump.
Since the day of the trip has been scheduled for a week or two ahead of time, there's plenty of time for Savane, who is a friendly sort who can't stop talking, to worm his way into West's life, where he is not wanted but ultimately tolerated. West is an old biker, with years of hard-living etched on his face. He takes cabs to the movies, where he is overly friendly with a teenage ticket-seller. Savane is tired of driving a cab, and wants to be a flight attendant, but his pregnant wife discourages him, wanting him home.
A plot contrivance that is a bit clunky leads Savane to bunk with West in the old man's motel room, and this allows Savane more chances to try to figure out just what is going on with West. The tension between the two characters, an odd couple if there ever was one, propels the film along at nice clip, leading to the fateful and vertiginous day at Blowing Rock, where the wind is so strong that an object thrown from the edge can go straight up.
This is essentially a two-person story, and because the characters are so sharply drawn and well-acted Goodbye Solo is a pleasure. But I think Rahmani's greatest move is to resist sentimentality. While Savane worries about West's motives, there is no third-act miracle that could be found in a Hollywood film. Each character is true to his nature, and the ending is inevitable, without being predictable.