Truth is a story of two girls in their senior year of high-school: Lee Ja-young (Choi Ji-Woo) and Lee Shin-hee (Park Sun-Young). Ja-young is smart and talented, with a bright future ahead of her. The number one student in her school, she hopes to make it into a top college. Shin-hee is the daughter of a powerful senator, and is a rich, spoiled brat. Mediocre at best, Shin-hee is able to lord over Ja-young because her father works for Shin-hee's father, and her family lives in Shin-hee's basement. As the school year progresses, Shin-hee takes advantage of the power she holds over Ja-young, holding over her the threat of her family losing everything. Ja-young's sweetness holds out, and the truth in her character attract people to her in a way that Shin-hee, for all her money and prestige, can't come close to. This becomes clear as Shin-hee's boyfriend starts to notice Ja-young.