As a child, singer Iarla Ó Lionáird witnessed the extraordinary impact that Seán Ó Riada had on Cúil Aodha in the Irish-speaking area of Cork in the 1960s. On the 75th anniversary of Ó Riada's birth, Ó Lionáird teases out the composer's vision as represented by the choir he founded, and the song the choir constructed in the wake of Ó Riada's death – 'Sé Mo Laoch, Mo Ghile Mear...', the 'laoch' (hero) representing Ó Riada himself...