Howie shows up at Topanga's house on prom night, thinking that she is his date. Apparently, when she and Cory broke up, he asked her if she had a date and she said no. Howie misconstrued this as an acceptance to go to the prom. Although Cory initially wanted to send Howie off, Topanga convinced him to let Howie tag along by telling him otherwise, prom night wouldn't be "exactly, perfectly right." (And Cory really wanted it to be "exactly, perfectly right")
At the prom, Howie danced with Topanga once or twice. He also showed her off to his friend as his date. Later on, though, he and the woman at the rental car counter hit it off (he reminded her of her ex-husband) and she was going to take him home that night. They could be seen dancing together in the background.
Howie's dad drives a Plymouth.