Drawing on discourse analysis and interview data, this case study uncovers how a lesson study team, supported by a curriculum specialist and an experienced teacher, anchored anticipating of student learning in sound curriculum deliberation, which enabled novice teachers to teach effectively inferencing skills, a highly demanding domain, through an Aesop's fable. The team entered expansive learning when their dissonance arising from RL1 contradictions drove them to question their beliefs and make improvement decisions through rigorous justification on grounds of their values and utility. The team actively rehearsed the planned episodes and expanded the deliberation discourse into multimodal forms of actionable teacher support with strategies, metaphors, story maps and concrete props. The curriculum deliberation instilled in them the passion for making well-grounded judgements for student learning and brought them expansive learning to cross the boundary of curriculum making. Besides direct implications for early literacy education, the study suggests that lesson study start with curriculum deliberation as a principled framework to anchor and mediate teacher discourse and support teacher boundary crossing and identity making. More research is needed to build curriculum deliberation into teachable thinking strategies for teachers and develop their research capacity and an inquiry stance through mutual learning in research-practice partnerships to address the persistent problems of practice and make lesson study sustainable.