After a successful show at the Black or White event, the idol unit IDOLiSH7 finds themselves riding high on a wave of popularity, fielding numerous offers for performances and projects, much to the delight of the seven members and their manager. However, amidst their skyrocketing fame, Riku Nanase's health begins to deteriorate under the strain of their demanding schedule. With the renowned duo Re:vale expressing interest in them and the highly anticipated reopening of the Zero Arena on the horizon, IDOLiSH7: Second Beat tracks the group as they not only grapple with the rigors of the idol industry but also confront their personal struggles, all the while striving to meet the expectations of their devoted fanbase.