About

Among humans, a very rare few are born with a specific genetic trait. This gene is related to "voice" and "sound," and its carriers are broadly classified into two types. Those with the voice to command are called "Leads," and those who react and resonate with that voice are called "Chords." Humans without this special gene are referred to as "Normals." Leads possess a unique vocal ability not found in ordinary humans. A Lead's voice contains specific melodic information that only a Chord's nervous system can perceive, allowing them to convey certain words as "commands." The strength of the ability is not determined by the volume of the voice; a skilled Lead can establish a powerful command even with a low voice or a whisper. Commands are most effective when they are short and clear, such as "Stop," "Come," or "Look." On the other hand, a Chord's body contains a special sensory mechanism to receive a Lead's voice. While they hardly react to the voices of ordinary humans, hearing a Lead's voice stimulates their nerves, causing physical and mental changes. This is not merely a phenomenon of "obeying an order," but rather a phenomenon where the body itself resonates with the voice. For this reason, the relationship between a Lead and a Chord is often compared to music, described as "the Lead playing the melody, and the Chord resonating along with it." The reaction between the two occurs in stages. The first is "Response." This is a state where the body reacts only at the moment a command is received, and the Chord can still resist through their own will. Next is "Resonance." By repeatedly receiving the same Lead's voice, the resonance strengthens, and the body begins to react just by becoming aware of a command. Beyond that lies "Submission," a state of obedience. It becomes difficult to resist the Lead's commands, and the Chord becomes intensely conscious of the voice itself. The deepest stage is "Dominance." The Lead's voice strongly influences the Chord's actions, to the point where they prioritize commands over actions they would normally decide for themselves. However, not all Leads and Chords react with the same intensity. Each gene has its own unique "melody," and compatibility exists. If compatibility is poor, "Dissonance" occurs, making commands weaker or causing physical strain. If compatibility is good, "Harmony" arises, and those with an extremely high synchronization rate reach a state called "Perfect Chord." Two people who have become a Perfect Chord react exceptionally strongly to each other's voices. In particular, the Chord begins to recognize that Lead's voice as a special sound; while they might resist commands from other Leads, they resonate powerfully with their unique partner's voice. This special Chord is called a "Primary Chord." A Lead is not an absolute ruler. Using strong commands places a burden on the Lead themselves, and as they approach a Perfect Chord state, the Chord's emotions and physical condition may be transmitted to the Lead. In other words, while the Lead dominates the Chord, the Lead is also influenced by the Chord. Though they are "the one who dominates" and "the one who is dominated," they cannot produce a perfect sound without each other's existence. This is a story that takes place at a certain all-boys school, "Kanon High School."