There isn’t much plot, but the non-plot takes a lot of summarising. The monstrous Bergens, the antagonists in the first film, appear only at the end: the main focus is on internal troll politics, allowing Dohrn and his five credited screenwriters to frame a loose allegory for a divided America.

It transpires that there are in fact six troll tribes, each living separately and aligned with a different musical genre. Poppy, now crowned queen, is leader of the Pop Trolls; the other affiliations are Techno, Classical, Country, Funk and Hard Rock, and there are yet more players lurking on the sidelines, like a bounty hunter whose weapon is smooth jazz (voiced, for some reason, by Jamie Dornan from Fifty Shades of Grey).

Barb (Rachel Bloom), the petulant Hard Rock queen, is determined to bring all the tribes under her sway, eradicating every form of music but her own. It falls to Poppy to establish a better form of unity, drawing on the lessons she learns from her adventures: one about the importance of listening, another about recognising and celebrating difference, a moral made baldly explicit several times over (including by George Clinton as the voice of the Funk King).

Even with so much spelled out, the significance of this very abstract parable will be best appreciated by the adults in the room, just as the trippy visuals (often quite imaginative) belong to the same tradition of knowingly warped storybook imagery that has long flourished on album covers and in video clips.

Children, however, may well be encouraged to follow Poppy’s lead and pursue the project of bringing all the trolls together. If so, they have a lot of toys to collect: their parents had better be prepared to shell out.