India gets under your skin and into your blood. There just isn’t anywhere like it. You don’t fall in love easily. One day you are walking in heaven and believe you have found God, the next you want to scream, drop everything and go home. And eventually you do, but a piece of it stays lodged inside. Like Trishna, Michael Winterbottom’s hotly anticipated new film.

Winterbottom has based this new epic (very loosely) on Thomas Hardy’s 1891 novel Tess of the D’Urbevilles, condensing the two principal male characters into one – Jai Singh, played by Riz Ahmed, one of Berlin 2012’s Shooting Stars. The heroine Trishna – the breathtaking Freida Pinto – is a poor, peasant girl who is forced by circumstance to take a job in the hotel of Jay’s father – a brief but brilliant appearance from Roshan Seth. Jay leads Trishna into a despotic relationship, one in which we are never sure about what Trishna is thinking or feeling.

This ambiguity was frustrating and I came close on many occasions to throwing in my interest. Why would Trishna drop everything and run away with Jay to Mumbai if she had previously fled from him for destroying her virtue? Most of the story progressed in this patchy fashion, sewn together with some indisputably gorgeous shots and a divine soundtrack – which hopped back and forth between the superior traditional Indian score and a classical score: its redeeming features.

Freida Pinto is It right now. And so one would expect a show to match. Unfortunately, we are left feeling that in this instance she is more pretty face than performance. The scenes that require her to perform manual labour – and there are a fair few of these – are awkward and almost clumsy. Even her Bollywood dancing, something Trishna is meant to love, is wooden. Just when I was ready to surrender to disappointment, the final quarter of the film does a U-turn in tempo. The plot becomes engrossing and Pinto manages to throw herself in with passion that was lacking before.

But this is Riz Ahmed’s film. I woke up in the night and stayed up thinking about his performance. What is so incredible are his presence, beauty and naturalness. And those eyes! He switches from the caring and noble lover in the first half of the film, to the frightening and tyrannical exploiter in the second half and is one hundred percent perfect in both roles. Ahmed does a gallant job of lifting what is essentially a very weak screenplay. Luckily, this is not a story told primarily with its words, but through the overall sensual experience and the magnetic chemistry (not all of it happy, mind) of Jay and Trishna.

If you were thinking about seeing Trishna, do go while it is on the big screen. These sights and sounds need to be experienced large and loud. Go and see it for the magical music, a beautiful couple, Ahmed’s unforgettable performance and a small, sublime cinematic vista onto one of the world’s most special kingdoms. I may not have enjoyed every minute, but it has left its mark on me.

Cruel Chemistry: The unforgettable Riz Ahmed as Jay and heart throb Freida Pinto as Trishna