When aging matriarch Suni is summoned to South Korea from the US to handle the sale of a family property, memories that she had long left behind come flooding back. In a prolonged flashback, the film shuttles us back to the 1960s when Suni (Park) was a teenager. Ailing physically from lung problems and emotionally from the death of her father, Suni, along with her younger sister and now single mother, moved to a large house in the countryside with the promise of fresh air. What the cobbled, quirky family finds is a wild child (Song) hiding in their barn, and a person to fill their emotional gap. Assumed to be an orphan from the war, they take the boy into their home, clean him up, and discover a curious yet somewhat ill mannered and mute naïf. Suni, rebellious by nature, finds solace in this interesting yet beautiful young man they name Chul-soo. Committed to taming his unruly impulses--like eating all the food in sight as soon as it is set on the table--Suni takes it upon herself to train him.
Much of the exposition of the story plays like a rom-com, as Chul-soo gets comfortable with his new family and gets close to Suni. There's a subtle charm to their relationship and an irresistible sympathy toward Chul-soo'd naïve ways. But evil lurks, not in Chul-soo's beastly nature, but in the jealousy of Ji-tae, a foppish young benefactor to the family who expects to marry Suni. Ji-tae's unwanted advances on Suni bring out the guard dog in Chul-soo, exposing his emotionally charged ability to transform. Ji-tae is keen to eliminate his competition and reveal Chul-soo's unnatural powers by exploiting his protective nature. The mano a mano of cunning against virtue that ensues is meant to provide some dramatic thrust of the film, but instead it flattens the dynamic characters into rote recitation of inane plot devices: the covert government science experiment, the trickery of a villainous heart, and the inevitable loss of innocence.
A Werewolf Boy unfortunately never veers from pedestrian paths, delivering a minor fairy tale that merely flirts with genre. Action and violence are fleeting, and the supernatural elements are locked to melodramatic earthly dimensions of the human heart. But those affairs of the heart, as drawn out as they get, have some resonance beyond painting a pretty picture. Back to the present, the final moments of the film emanate an unexpected aura of guilt, regret, and sorrow. Fifty years later, Suni is forced to face the promises she made in her youth and the choices she made in life. The untidy bow wrapped around the epilogue may be the only evidence of Jo's rebellious nature, assuming its still there. Although the film effectively pulls gently on the heartstrings, it struggles to assert a personality within the well-worn confines.