In Thea Stilton and the Race for the Gold, the Thea Sisters travel to Brazil during the summer Mouselympics to support their friend Beatrice, a talented athlete training for the Summer Olympics. However, their visit takes an unexpected turn when strange occurrences begin disrupting the team's preparations: sneakers go missing, batons disappear, and tensions rise among the athletes. Determined to help, the Thea Sisters delve into the mystery, aiming to uncover the cause of these disturbances before the big race.