A young orphan named Tomás is taken in by Maire O’Donnell to reside on a charming Irish island, where he encounters new companions, hidden caves, and a stranded baby seal on the shore. However, Maire’s hesitant husband, Alec, struggles to embrace Tomás as part of the family, leading the boy on a journey of adventure and self-exploration. This journey reveals how rainbows can appear both around us and within our hearts.