Nationalistic projects and bloody conflicts around the world testify to the nation's determination to fight the forces that threaten its sovereignty. The present discussion reads Cantre'r Gwaelod (1996) – a Welsh book from the European Picture Book Collection – as an attempt to defend the idea of national identity. The colonial and postcolonial cultural battles that have been taking place in Wales, and elsewhere, for the duration of centuries have not left children, or children's literature, unaffected. When the Welsh picture book is situated in its local environment, it becomes apparent that it advocates resistance to `foreign invasion'. The waves that drown the glorious ancient history of Wales are the waves of English colonialism. Younger generations are expected to amend this historical discontinuity and reclaim their nation's glory. The subjective positioning of both child-protagonist and child-reader is designed to facilitate national regeneration. I find resistance to colonialism important and legitimate, but I also find it problematical when it takes the form of monolithic nationalism. While children may prove capable of resisting nationalistic appropriation of their minds and bodies, the powerful institutions that support it often leave little space for resistance.