“Song of the sea” is a spectacular film that explores the Celtic myth of Selkies, a mystical being that can change form between human and seal, through a simply-told and heartwarming story about a brother and a sister. “Song,” a traditionally-animated film, is also a visual feat. And despite a few moments in which the visual eclipses the story “Song” is a successful continuation of animation storytelling.

The film, by director Tomm Moore (he was nominated for an Academy Award for “The Secret of Kells”) is centered around two characters, Ben, the older brother, and Saoirse, his younger sister, who still hasn’t learned to talk at the age of six. At the beginning of the film, the relationship between Ben and Saoirse is strained as Ben partially faults Saoirse for the death of their mother who disappeared after she gave birth to Saoirse. At the night of Saoirse’s sixth birthday, she plays a shell flute that their mother left behind and releases a magical tune that awakens the mystical beings in the area. She also discovers a special coat that allows her to turn into a seal when she is in water. However, when Saoirse is discovered to be playing in the sea, she and Ben are, at their grandmother’s behest, shipped to the city so that they can be far from the hazards of the ocean. The film then tracks Ben and Saoirse’s journey home and the aftermath of Saoirse embracing her Selkie identity.

While the unfolding of the story is a slow burner, especially compared to the brisk pacing of contemporary Disney productions, the emotional heart of the film shines brightly thanks to brilliant performances of voice acting from its cast. In addition to its tender exploration of the brother-sister relationship “Song” also probes the themes of grief and loss. Despite her absence, the figure of Bronagh, the mother, dominates the film, as the central characters, Ben, Saoirse, and Ben and Saoirse’s father, are all in different ways still emotionally mired in the aftereffects of her death. The parallels established between characters of the real world and the magical realm also cleverly reinforce the film’s significance about how repression of grief might hinder, and not support, a person’s attempts at healing. While children might find the story of the mythical creatures enticing, adult viewers might find resonance and even solace from the film’s treatment of a family coming to terms with absence and death.

One of the strongest merits of “Song of the sea” is that it can be seen as not merely a journey of the heart, but also of the eye. Visually rapturous, the film is a marriage between the lush aesthetic of a children’s book and the equally evocative powers of old myths and legends. Yet despite its accomplishments in design, “Song of the sea” is not entirely without fault. The episodic nature of the returning-home narrative shuttles the viewer from one exotically magical location and one eccentric yet negligible side character to the next, sometimes detracting from the core of the story, which is the brother-sister relationship between Ben and Saoirse. And while the mythological side characters and their situated backgrounds provide much room for entertainment and spectacle, they seem like distractions that crowd the story without, in the exception of the “villain” Macha, fulfilling much value other than background exposition for the Celtic myths.

Moore strikes an awkward balance between the elaboration of legends, the showcasing of design and the development of the plot. And it is a balance that, sometimes, wobbles. But there are enough moving and visually beguiling moments to counteract such misfires. And while it is the quieter emotional moments of the film, such as a frail Saoirse uttering her first word, “Ben,” that make the whole trip through the film’s magical world worthwhile for me, for others, it may be the rapturous use of color and design that may leave a lasting impression, instead.

“Song of the sea” premiered at the 2014 Toronto International Film Festival.