Tommy is a down-on-his-luck 31-year-old man who's been drinking too much since he broke up with his girlfriend, Theresa. She dumped him after he got fired from his job as a mechanic. Now he spends most of his time at the Trees Lounge, a rundown bar in Long Island, where he commiserates with his fellow regulars.
Tommy's best friend is a middle-aged drunk named Mike, who's always trying to find ways to make some quick cash. He talks Tommy into a job driving an ice cream truck, which seems like a good opportunity until he realizes how hot and noisy it is. He also has trouble getting paid because the guy who owns the truck is a deadbeat.
Meanwhile, Tommy is still in love with Theresa, who's moved on and is dating a guy named Rob. He stalks her and shows up at her house unannounced, hoping to win her back. He's also drawn to Debbie, Theresa's teenage niece, who hangs out at the bar and flirts with him. He invites her to ride along on his ice cream truck route and they start fooling around.
When Debbie's father finds out about the affair, he forbids her from seeing Tommy and threatens to beat him up. Tommy tries to win her back by buying her presents and telling her he loves her, but she realizes he's just using her to forget about Theresa. She breaks up with him and he spirals even further out of control.
In the end, Tommy is arrested for drunk driving and loses his driver's license. He wanders off into the night, unsure of his next move. The movie ends with a shot of the empty Trees Lounge, a symbol of the emptiness and aimlessness of Tommy's life.