Do you wanna build a franchise? Maybe Jennifer Lee and Chris Buck didn’t realise this was what they were going to do in creating their sensational Disney animated musical Frozen in 2013, with its lethal Broadway-style show tunes written by Kristen Anderson-Lopez and Robert Lopez and scored by Christopher Beck. It was all about Elsa, the beautiful blond princess with supernatural icy powers, a story based mostly on Hans Christian Andersen’s The Snow Queen, along with the still unacknowledged influence of Frozone from The Incredibles. Now its fiercely anticipated sequel is here.

In 2013, parents of young daughters didn’t realise how their every waking moment and all of their disposable income was going to be dominated by Frozen, with Elsa toothbrushes, Elsa hairbrushes, Elsa dolls, Elsa backpacks, Elsa snow globes, Elsa onesies, Elsa lunch boxes, Elsa sequin slippers, all to be assembled at Frozen-themed sleepovers.

And for all ages there was the sensational song, Let It Go, which hit the nerve centres of adults and children alike with the power of crystal meth. Exiled from her homeland, in her magnificent isolation, Elsa realises that she no longer needs to hide her icy superpowers and can use them freely and be herself – she can let it go. All of us, women and men, gay and straight, after a few glasses of wine can feel the karaoke thrill of that amazing song, which subtextually speaks to grownup themes. It’s Gloria Gaynor’s I Will Survive for a new generation, building to a defiant voice-cracking melodrama on the famous line: “The cold never bothered me anyway.” Sadly, there have been numberless vulgar spoof versions on YouTube, including Let One Go, a notorious version in praise of farting.

Part of the strangeness of watching Frozen II is wondering if there will be a specific “sequel” to Let It Go, a new number that takes its sentiments forward in some way, and it is simultaneously a mild disappointment and a vague relief that there isn’t, or not exactly, although there are some hummable, catchy tunes. It’s notable that Elsa (voiced again by Idina Menzel) is still seen fundamentally as a singleton, where it is her devoted sister Anna (voiced again by Kristen Bell) who is the one with the romantic pairing, with Kristoff (Jonathan Groff).

The sequel takes us some years forward from the end of the first film into the happy ever after, but begins with a flashback to Elsa and Anna’s childhood, in which their parents King Agnarr (Alfred Molina) and Queen Iduna (voiced by Evan Rachel Wood) tell the little girls at bedtime about the enchanted forest that lies to the north, ruled by four spirits, symbolised by four standing stones: earth, air, fire and water. It is a place with unhappy family associations. Now in the present day, Elsa hears a strange voice calling her from the forest, and she realises that she must journey there to confront and dispel a family secret, naturally with the well-known and well-loved cast of characters by her side: Anna and Kristoff and also Sven the reindeer and the legendary snowman Olaf (Josh Gad).

That sinking feeling … Frozen II. Photograph: Allstar/Walt Disney Pictures

It’s nice to see these figures again, but I couldn’t help feeling that there is something a bit underpowered and contrived about the storyline in Frozen II: a matter of jeopardy synthetically created and artificially resolved, obstacles set in place and then surmounted, characters separated and reunited, bad stuff apparently happening and then unhappening. At times, Frozen II almost felt like an extended bonus featurette that could have gone with the Blu-ray edition of the first film. Having said that, it looks and sounds good, with a stirring central song for Elsa entitled Into the Unknown, the curtain-raiser for her encounter with the primeval forces of the forest.

Olaf of course is still a scene-stealer, with a great song about how baffled he is by what’s going on, entitled When I Am Older (“This will all make sense when I am older / Some day I will see that this makes sense / One day when I’m old and wise / I’ll look back and realise that these were all completely normal events …”) He has a very funny scene in which he has to recap the events of the first film in about 10 seconds for people who are not aware of them. There’s also an amusing running gag about Kristoff’s maladroit attempts at a marriage proposal being misunderstood by Anna. It’s an entertaining revival, though a thaw is beginning to set in.