Peter Sullivan and colleagues present a report on an initiative at a Victorian primary school which embraced opportunities offered by purposeful collaborative professional learning communities. They utilised a form of Japanese Lesson Study as part of their approach. There are three parts to the story of this initiative: (1) a description of the approach to professional learning; (2) an explanation of the model of instruction being explored; and (3) a summary of the 'polished' lesson on middle primary mathematics (fractions).