We have Siddharth (Emraan Hashmi) and Sonia Mehra (Shamita Shetty), who are both police officers.

Then, there is Anna (Udita Goswami) and Shaun Verghese (Siddhant Kochchar). But Shaun is a criminal who enjoys beating up his wife.

The film opens on an angry Siddharth as he throws his wife out of his house.

So with his marriage on the rocks, Siddharth meets Anna Varghese one night while drowning his sorrows. He gives her a lift and one thing leads to another as they end up spending the night together.

After their initial encounter, lonely Siddharth decides to have an affair with Anna who inturn becomes pregnant.

But their happiness is short-lived when Anna discovers that she is suffering from cancer, but does not have the money to pay for treatment.

Desperate to help Anna, Siddharth takes an irrational decision by giving her the money he had recovered in a drug raid. This is Siddharth's final effort to save Anna.

Anna dies in suspicious circumstances that very night, adding further tension for Siddharth. What's worse, his ex-wife heads the investigation.

Siddarth must now race against time to find the real truth behind Anna's murder, recover the drug money and win his wife's back.

The film is fast paced and gripping, keeping you engrossed throughout. There is never a dull moment as Siddarth digs himself deeper and deeper into a hole as his wife starts to uncover the evidence behind Anna and Shaun's murder.

Full credit goes to debutant director Mohit Suri for handling all the situations with realism, especially the climax scenes which catch you unawares. This happens to be the biggest surprise of Zeher.

Being a thriller, there is not much room for song sequences but the ones which director Suri includes add some welcome respite to the tense proceedings.

These include 'Agar Tum Mil Jao Zamana Chhod Dennge Hum' and 'Woh Lamhe Woh Baatein' which are doing well in the music charts.

Zeher works not only because of a good script but also the performances given by the three lead stars.

Emran impresses with his acting talent. He is superb throughout the film as the helpless hero trying to cover up his tracks.

But it is Shamita Shetty who is full of surprises. Given a meatier role, this actress can certainly move mountains! Zeher might just end up being a turning point in her career.

As for Udita Goswami, she gets under the skin of her character with ease as she provides the right impact as the seductress.

Overall, Zeher (meaning poison), is a well crafted thriller which keeps you engrossed throughout. Not to be missed!

Reviewed by Manish Gajjar
BBC Shropshire Bollywood