When Noah and Zara stumble upon a strange triangular device buried in the sand at Thirroul Beach, their quiet coastal town suddenly feels alive with hidden energy. Each strum of Noah's guitar, each note of Zara's voice, awakens a forgotten system beneath the shoreline - one that responds not just to sound, but to memory, trust, and emotion.With their dog Vader at their side, the siblings follow a trail of resonance points across headlands, boatsheds, tunnels, and bush tracks. Each frequency reveals a new piece of the mystery - and a new test of who they are to each other.Part sci-fi adventure, part emotional journey, Frequency 11 is a middle-grade novel about courage, connection, and the secret rhythms that hold us together.