In this family superhero animation with a twist, the monster that must be grappled with by our hero is parenthood – and specifically baby-care. We open in Odaiba, Japan, with a flashback to the childhood of Ken Sato, whose dad is passionate about kaiju, the giant monsters of Japanese pop culture (of which Godzilla is probably the best known in the west). Twenty years later, Ken is a baseball star by day and gigantic kaiju fighter Ultraman by night (or indeed, whenever the kaiju show up) though like his father before him, it’s more about protecting people and monsters from each other than a standard slay-the-beast trajectory.

Things get complicated when he finds himself unexpectedly landed with an orphaned baby kaiju to look after. Ken is not prepared for single parenthood, and is duly rushed off his feet managing the competing demands of work and adopted infant, getting covered in bodily fluids in the process, and making all sorts of delightful discoveries about the limits of his own knowledge. “Babies get acid reflux?” he exclaims despairingly at one point, in a line that feels rooted in lived experience. Mind you, this baby is 35ft tall and breathes fire, so, you know, a challenge even for Supernanny.

While Godzilla has served for decades as a metaphor for anxieties around nuclear power, this is probably the first creature feature where the kaiju functions as a vehicle for a Three Men and a Baby-type narrative about muddling through as a new parent. It’s a decent metaphor as it happens: regular human babies feel like both the smallest, most vulnerable thing in the world, and also the most massive and important, and this kaiju baby is similarly both defenceless and outsize at the same time. With a bit of trimming of other subplots, the film could have focused more tightly on this premise; instead it drags a little in places, despite the appealing animation style, which really comes into its own during the action sequences.

• Ultraman: Rising is on Netflix from 14 June.