The Liability

The Liability (also known as The Hitman's Apprentice) is a 2013 British black comedy crime-thriller film directed by Craig Viveiros and written by John Wrathall. The film stars Tim Roth, Talulah Riley, Jack O'Connell and Peter Mullan. The film is about a teenager sent to do a day of driving for his mum's gangster boyfriend, which leads him into the world of crime.
Young and naive 19-year-old slacker, Adam (Jack O'Connell), lives with his mum, Nicky (Kierston Wareing), in the home of her intimidating gangster boyfriend, Peter (Peter Mullan). After Adam wrecks Peter's luxury car, he demands Adam work to repay him, and he sends Adam to drive for a criminal associate. When Peter leaves, Adam looks through Peter's laptop and views an incriminating video that shows Peter hitting a woman.
The next day, Adam goes on the road with ageing hitman, Roy (Tim Roth), and he enters a world of murder for 24 hours. After Roy kills a man, Danil, who was living in a camper in the woods, he tries to force Adam to shoot and kill a young woman (Talulah Riley) who witnesses them dismembering the dead body. Adam refrains from doing so, giving her the chance to escape and drive away in their vehicle, along with the victim's dismembered hands.
Not pleased, Roy uses Adam to pretend to hitchhike and they carjack a camper van from an elderly couple. They call the girl on Adam's phone that was left in the car she took, striking a deal to give her £7000 in return for the bag of dismembered body parts that was left in the vehicle, even though Roy doesn't actually have the entire amount. Roy robs a diner to make up the rest. He holds the diner employees at gunpoint and uses them as hostages to make sure the deal goes through.
Having reclaimed the bag, Roy and Adam plan to switch vehicles and dispose of the evidence. However, Roy knocks Adam unconscious with a spanner at a quiet roadside area. Before Roy can kill and dismember his body, the girl, who followed them, runs over Roy and kidnaps Adam.
Retreating to a water pumping station, the girl ties Adam to a rail upstairs. She claims her sister was sold in a line of sex trafficking, by Sergej to Ivan, to Danil and finally to an "Englishman". She shows Adam a photo of her sister who bears resemblance to the woman in the video on Peter's laptop. Swiping through the photos on Adam's phone the girl discovers a picture of his mother and her boyfriend. She asks Adam for Peters name, claiming Sergej and Ivan also had his picture.
Roy finds his way to the water pumping station and confronts the woman, starting to fight with her. Adam manages to free one of his hands and retrieve Roy's fallen gun. Regaining his memory, Adam realises Roy attempted to kill him. Angered by the betrayal, he fires off shots, wounding Roy in the torso as the girl flees. Roy pleads with him to stop shooting and tells Adam he was given orders to kill him, but no reason, with Adam's death meant to be part of "the job" all along. Adam realises it may be because he saw the video incriminating Peter of sex-trafficking and assault.
They leave the pumping station, finding out the woman left behind the car, money and other belongings she had taken. Adam drives Roy in their stolen van to a church for Roy's daughter's wedding. During the ride, Roy reveals he spared Adam's life because of his innocence and tells him he has a second chance at life, while Peter believes he's close to death. After dropping off Roy at the church, where his fate is left ambiguous, Adam takes the van away to set fire to it and destroy the cellphones and any evidence linking them to the murder done on their travels, but keeps the gun.
Adam returns home, confronting Peter with the gun and alerting his mum Nicky to his double-crossing ways. Adam attacks Peter, who gets a hold of the gun, Peter knocks out Adam's mum and drags him out to the garage. There, the woman shows up and shoots Peter for what he did to her sister. Peter starts to strangle her until she stabs and kills him.
The woman gets in her car, opens the passenger door and gives an inviting look to a bewildered Adam.