Johannes “Jojo” Betzler (Roman Griffin Davis) is an enthused 10 year-old member of the Hitler Youth; so dedicated to the Nazi cause that he has Adolf Hitler (Taika Waititi) for an imaginary friend and dreams of showing enough bravery to defend Germany on the front lines. When he discovers his mother (Scarlett Johansson) is hiding a Jewish girl (Thomasin McKenzie) his beliefs are suddenly and powerfully challenged.

Jojo Rabbit, written and directed by Waititi and based on Christine Leunen’s novel Caging Skies, is a satirical comedy seemingly purpose-built to elicit controversy and debate. In truth it is more bark than bite, superficially shocking its audience with comedic Nazi propaganda and exaggerated antisemitism but never giving its characters enough dignity to convince us of their beliefs. That does open the film up to a huge debate over social responsibility: is it appropriate to transform Nazis into figures of fun when real-life Nazis exist today and represent an actual danger to society? Waititi does try to have it both ways to an extent – the film’s second half introduces a welcome element of serious drama, but never hews too far from its combination of slapstick and absurdity.

You can strip away the hijinks and attention-grabbing comedy bits, however, and what you will find underneath is remarkably conventional. It is essentially a feel-good drama about a boy discovering his own sense of morality during war-time. It just happens to be a remarkably enjoyable feel-good drama; it hits the right beats, hits them in the right way, and leaves the viewer rooting for Jojo to succeed in changing, his Jewish houseguest to survive, and for the Nazis to lose the war. Waititi’s tightly developed and well-plotted screenplay is an excellent example of its genre. The over-the-top attention-grabbing gags are essentially there for the audience to pay attention.

If the film does succeed – and on its own terms I strongly believe it does – it is because it has been brought to life by an exceptionally strong cast. As the titular Jojo, nicknamed “Rabbit” by bullies in the Hitler Youth, Roman Griffin Davis balances excellent work both in a dramatic performance and in using comic timing. Archie Yates is another excellent juvenile actor, boasting a charmingly round face and glasses and a remarkable ability to sell a funny joke. A group of comedic actors play a fine group of parodic Nazi officers, including Rebel Wilson, Sam Rockwell, Alfie Allen, and Stephen Merchant – particularly strong as a weirdly upbeat Gestapo investigator.

Scarlett Johansson is a surprise as Jojo’s mother Rosie. As a child, Jojo is not quite observant enough to read between the lines and recognise her as an anti-Nazi resistance member, but for the audience she is a tremendously subtle presence: living without her husband, turned to drink with despair, and secretly doing what she can to disrupt the German war effort. Her performance is light and funny, but tinged perfectly with a drunken melancholy. It is probably the best performance of her career.

Looming over all others with a ridiculous presence is Waititi himself as an imaginary, gratingly contemporary imaginary Hitler. He swears. He rages. He sulks more than one might expect. He is an amusingly formed child’s parody of what the real Hilter might have been like, and only really missteps in his final unnecessary scene. The film would have been stronger without it. As it stands the character largely works because of how little like the real Hitler he is; getting played by a Jewish Maori is pretty much the best way to treat a real man so bigoted and loathsome. (Waititi has boasted in interviews of doing no research in how to play the character whatsoever, ‘because he’s a c*nt’.

Jojo Rabbit is a hugely entertaining piece of work, but its well-publicised comedic bits are only really an avenue to draw the audience in. What makes the film excel are the human moments weaved in between the comedy. The growing relationship between Jojo and the Jewish refugee Elsa, or Rosie’s pained tolerance of her son’s idiotic and ignorant zealotry. The genuine child’s friendship between Jojo and Archie Yates’ stupidly amiable Yorki. The film’s final scene, which is honestly pitch-perfect. This is absolutely one of the best films of 2019, but probably not for the reasons you expect – and that makes it all the better.