Warning: spoilers ahead for episode five of The Serpent.
Ever since Nadine (Mathilde Warnier) was told about the true nature of serial killer Charles Sobhraj (Tahar Rahim) from the recently-escaped Dominique (Fabien Frankel) in The Serpent, she has demonstrated that she is not only compassionate, but extraordinarily brave as well.
Having confided in Dutch diplomat Herman Knippenberg (Billy Howle) and his wife Angela Knippenberg (Ellie Bamber) about the crimes Charles has committed, Nadine is desperate to continue to help the couple with their investigation, even if it means putting herself in harm’s way.
But while she may have initially been able to convince Charles and his accomplices Monique (Jenna Coleman) and Ajay (Amesh Edireweera) that she can be trusted, it becomes clear in episode five that Charles can see through her friendly smiles… leaving her in grave danger.
Fortunately for Nadine, Herman has made significant headway with the police in Bangkok, with the officers complying with his request that Charles (known as Alain Gautier), Monique and Ajay be taken in and their property raided.
But as Herman, Angela, Nadine and her husband Remi (Grégoire Isvarine) toast to their success, it becomes abundantly clear – even before we witness Charles and co escape from prison – that their celebrations are far too premature.
Just like the reptile he is commonly compared to, Charles slithers out of Herman’s grasp yet again by using his wily ways to convince the police that he is an American citizen called David Gore, who has simply been staying in the residence of the real Alain Gautier.
While just like Herman, the audience is fully aware that the passport of David Gore is just one of the many forged passports Charles has obtained from his numerous victims, the other passports, which could provide enough proof to keep Charles in chains, are nowhere to be found.
Despite his innate wickedness, Charles is still able to manipulate some individuals to do his bidding no questions asked.
One such individual is Suda (Chicha Amatayakul), a jeweller he is having an affair with who just so happens to be the daughter of a colonel in the police force. What a coincidental, useful little connection.
Being the forward-thinking criminal that he is, shortly before he is apprehended, Charles places a briefcase containing all of the stolen passports in Suda’s care, winning her over with a dazzling engagement ring and a heartfelt request that she look after his treasured possession for a few days.
Just as Herman and Angela suspect they could have Charles ensnared for good, they learn that he, Monique and Ajay have all fled jail, thanks to the help of an easily-bribed police officer.
Following a quick trip to Suda’s home, Charles retrieves the briefcase and the engagement ring – which he gives to Monique – before speeding away to who knows where, Herman’s trail on the murderer going cold yet again.
And Nadine, having been found out by Charles, is given a stark warning from Ajay – that she is being watched.
No matter where Charles is in the world, he will continue to pose a threat to anyone who dares get in his way.
The Serpent returns next Sunday at 9pm on BBC One and is available to watch on BBC iPlayer.