The latest feature from the Danish screenwriter and filmmaker Anders Thomas Jensen follows Anker (Nikolaj Lie Kaas) as he returns from serving a 15-year prison sentence for bank robbery to find that his brother Manfred (Mads Mikkelsen) has developed dissociative identity disorder (DID). Manfred now believes he is John Lennon, which would be funny, except for the fact that he can’t remember where he buried the stolen money, and Anker needs to find it so he can pay back some very dangerous people.

From there, the plot of The Last Viking tumbles into utter chaos. Anker kidnaps Manfred from a psychiatric hospital along with other DID patients who also believe they are Beatles members. His idea is to surround Manfred with like-minded people and hopefully jog his memory about where the money is. The storyline is sprawling yet ridiculously entertaining, but we are grounded in reality by Anker; Lie Kaas’ permanent exasperation is the source of many a comedic moment.

The funnier side of DID is also explored, especially regarding the other ​“Beatles member” who believes he is George Harrison, Paul McCartney and Heinrich Himmler all in one. Ultimately, however, the condition and its causes and effects are handled respectfully. Mikkelsen’s performance understands the gravity of this, steering away from slapstick and caricature to craft a character you desperately want to root for. It’s a delight to watch him swap his usual intense and brooding villain roles for the childlike and soulful Manfred.

DID can arise when a person grows up dissociating from traumatic events in childhood. In The Last Viking, the trauma behind Manfred’s condition is revealed through a series of brutal flashbacks that expose the brothers’ difficult childhood. This emotional weight is underpinned by the film’s sweeping orchestral score that grounds us after the more humorous moments. The cinematography offers nothing new, but wide shots that capture the harsh beauty of the Danish wilderness emphasise the isolation and desperation the brothers faced while growing up.

The Last Viking is a difficult film to categorise. It’s been described as a black comedy, but that doesn’t quite do it justice – it has notes of a heist movie, elements of an ​“underdogs getting the band back together” tale and even uses a folklore-esque animation as the film’s opening sequence to introduce Manfred’s childhood obsession with Vikings, something that helps him out later in life.

“People are more than one thing,” the pair’s sister says of Manfred, and when it comes to The Last Viking it’s never been more true. The film’s unpredictability and refusal to be categorised mirrors its protagonist. Beneath the chaos is the idea that, as human beings, we contain multitudes. And this isn’t a bad thing – the film argues that the only thing that can define us is those around us and how they treat us. If we’re weird but everyone else is also weird, doesn’t that make all of us normal?