Tsukushi Makino is a hardworking student from a lower-middle-class family who attends Eitoku Gakuen, an elite academy filled with the children of Japan’s wealthiest families. Her dream is simply to graduate unnoticed, but her plan fails when she defends a friend against the school’s reigning monarchs, a group of four wealthy and powerful boys known as Flower Four, or F4.

The F4 includes the volatile and arrogant heir to the Domyoji financial empire, Tsukasa Domyoji; the quiet, introverted, and handsome Hanazawa Rui; the charming playboy and heir to a tea ceremony school, Sojiro Nishikado; and the amiable Akira Mimasaka, who comes from a powerful family with ties to the underworld. These four rule the school with absolute authority, issuing a red notice to any student who crosses them, which encourages the entire student body to harass and bully the target until they are driven out.

After publicly defying Tsukasa, Tsukushi receives the red notice and finds herself the target of relentless bullying. However, refusing to be broken, she fights back, earning her the nickname tough weed and, unexpectedly, capturing Tsukasa’s interest. While the spoiled Tsukasa becomes increasingly drawn to her, Tsukushi develops feelings for the gentle and melancholic Rui, who is himself pining for his childhood friend, the famous model Shizuka Todo. This creates a complicated love triangle complicated by Tsukasa’s aggressive courtship and Tsukushi’s own stubbornness.

As the season progresses, Rui follows Shizuka to France, leaving Tsukushi to navigate her confusing feelings for Tsukasa. A pivotal moment occurs when Tsukushi and Tsukasa are trapped in an elevator overnight, sparking rumors that they are dating. Tsukasa’s older sister, Tsubaki, returns to support the unlikely couple, seeing in Tsukushi the same strong spirit she possesses, while their cold and calculating mother, Kaede, vehemently opposes the relationship and attempts to destroy Tsukushi and her family.

The narrative builds toward the Teen of Japan beauty contest, which Tsukushi enters on Tsubaki’s advice to win prize money to pay off a debt incurred by Kaede’s machinations. In a final confrontation, Tsukasa makes a wager with his mother: if Tsukushi wins, she can no longer interfere; if she loses, he will leave for New York to study business management. Tsukushi comes in second, but in a climactic moment at the airport, she finally confesses her love for Tsukasa, who gives her a Saturn necklace as a token of his devotion before departing.