Michael has just moved with his parents and baby sister into an old, derelict house. Shortly after, he discovers Skellig, a strange, extraordinary though pale and filthy being lying in the same rickety, old garage his parents had warned him to stay away from. But his parents are too preoccupied with Michael’s baby sister, who was born with a damaged heart, to notice.
While his parents worry about the critically ill newborn, Michael, unable to help his baby sister, nurtures his new, fragile friend instead. New friend and neighbour Mina - also an extraordinary girl in many respects – helps moving him into a secret hiding place away from the danger of being discovered. When they lift his body, the children discover what appears to be a pair of wings growing from his shoulder blades.
The strange man in the garage turns out to be a cross between a bird and an angel. Once his health and magical powers are restored, he returns Michael’s kindness and gives his baby sisters a new chance to live.