Arnau is a young boy who lives immersed in his own fragile world where he keeps drifting away. His only travel companions are a few singing birds: chaffinches, greenfinches, linnets and especially a goldfinch which has become the purpose of his life. Thanks to a careful training, no other bird sings so beautifully. And yet Arnau feels a big burden in his heart: his mother is imprisioned in the Vad-Ras penitentiary awaiting trial and things do not seem to get any better. Meanwhile Arnau is living with his sister Sole in a district in Barcelona that is undergoing deep changes and spends the afternoons daydreaming with his brother Sergi, who often accompanies their uncle Ramón to the old dogtrack. Things will come to a head when Arnau devises a scheme to help his distressed mother.