In the second season of 3-gatsu no Lion, Rei Kiriyama navigates his second year of high school while grappling with the demands of the professional shogi world and his personal struggles. Surrounded by diverse personalities in the shogi hall, school club, and local community, Rei's once solitary existence begins to unravel. Among these individuals are the Kawamoto sisters—Akari, Hinata, and Momo—who form a warm, familial connection with Rei. Through these newfound relationships, Rei discovers the shared emotional burdens everyone carries and learns the importance of both seeking and offering support. Despite the challenges of professional shogi life, including intense tournaments and formidable opponents, Rei's journey towards self-discovery and understanding unfolds. As he progresses in his shogi career, he grapples with the purpose behind his dedication to the game while navigating the complexities of his evolving relationships.