Folklore is life in Tomm Moore’s animated masterpiece, a stunning visual tapestry and a simple story about how any family’s grief for a lost loved one can be as deep and vast as a national mythology. Not that they’re gloating or anything, but Moore and artistic director Adrien Merigeau forcefully remind us what an animated film can do without plasticized 3D desperation, strenuous cleverness, or coyly self-conscious narrative formula. Song of the Sea’s richly digressive odyssey involves a widowed lighthouse keeper (voiced by Brendan Gleeson), a 10-year-old boy (Moone Boy’s David Rawle), and his mute but magical 6-year-old sister. Also: selkies (humans by land, seals by sea), an enchanted shell-flute, and a brokenhearted owl-witch with the voice of Fionnula Flanagan. Although obviously made with exacting care, and tirelessly gorgeous — every single image — the movie has an aura of effortlessness and aesthetic unity. Characters are rendered in an accessibly simplified style, nicely set off from the richer textures of lavish environments. Sibling bonds, and hostilities, play out naturalistically against supernatural circumstances, with subtle but tangible parallels between humans and their mythic counterparts. The music, by composer Bruno Coula in collaboration with the Irish band Kíla, is at once hummable and ethereal. Making its case that wistfulness is a magical force, Song of the Sea upholds the great Irish narrative tradition of extracting exquisite uplift from heavy sadness. It demonstrates, as maybe only a great animated film can, how ordinary life teems with wonder. This isn’t a trope or a technique. It’s a vital and enduring worldview.