In Jingle Belle, Isabelle (Tatyana Ali) is a budding singer and songwriter who dreams of stardom. She is also deeply in love with her high school sweetheart, Mike (Cornelius Smith Jr.), who shares her passion for music. Every Christmas, the two of them would perform a beautiful duet at their small town's annual Christmas Eve Pageant, captivating the audience with their love for each other and their music.
However, after graduation, Isabelle chooses to pursue her dreams at Juillard in New York, leaving Mike behind. They lose touch over the years, and Isabelle becomes a successful singer, but she never forgets her hometown and the memories she shared with Mike. When she returns to write music for the Christmas Eve Pageant, she is surprised to learn that Mike is now directing the show.
At first, Isabelle is hesitant to work with Mike, as she still harbors feelings of hurt and regret over their past relationship. But as they spend more time together, rehearsing for the pageant, old feelings resurface and they start to reconnect. Isabelle and Mike also discover that they share a common goal - to make the pageant a success and bring joy to the people of their town.
With the help of their mutual friend, Tony (Mark Taylor), Isabelle and Mike begin to collaborate on a new duet for the pageant. As they work on the song, they rediscover the magic they once had together and realize that they never really lost each other. On Christmas Eve, they take the stage and perform a stunning duet that leaves the audience spellbound. Isabelle and Mike finally put the past behind them and start a new chapter of their lives together.