The story focuses mainly upon 4 friends, Jo (Emma Roberts), Shannon (Ophelia Lovibond), Kerrys (Shanika-Warren Markland) and Cassandra (Tamsin Egerton). They all meet one other at a Diner, where they also see Dillon (Adam Deacon) and Smoothy (Bashy) getting chased by the police while drug-dealing. As Dillon is running past, he drops a stolen diamond (out of 15) in Cassandra's bag. He is unaware that Shannon has a big crush on Dillon as he always ignores her. The four then walk out and go home.
Firstly, the story focuses upon Shannon: as she walks into her home, she sees that her mother has left for good and her dad is sitting in the living room all alone. She loses her temper, gets a packet of "Pringles", two cans of spray-paint and runs away. She then runs over to Joanne's home, who has to rush to work, telling her she does not have time to talk. Later on, she is called over to Jo's work place by Jo; where she is told to leave. When she refuses, Dillon kisses Jo upsetting Shannon, so she grabs a Pringles box from the shop and runs. She is taken in by a woman who saved her from getting raped, but Shannon seems to find that the woman is looking for the Pringles box. This is later confirmed when she finds out that she is searching for "15 diamonds". One is already in Cassandra's bag, whilst the rest are in the Pringles can which had fallen out of Shannon's bag earlier. She escapes by knocking the woman out with the bathroom door. She finds the diamonds by going back to the bench where she was almost attacked. Her story ends with her holding the diamonds above a bridge, suggesting she is about to jump and commit suicide.
Secondly, the story moves onto Cassandra, who visits New York to meet up with a man called "Brett" she has met on the internet. The meeting ends with her having sex with him. She suddenly feels light headed and falls asleep, and in the morning uses an epipen to pull herself together. She discovers all her possessions gone except for her handbag containing a diamond. She also finds the letter that Shannon has been looking for, which was written by her mother. She later goes to "Brett's" house to later find that "Brett" is a stalker who hacks into Cassandra's computer taking videos of her. When the fake Brett comes, she knocks him out but later escapes chasing her down the street where she is rescued by a black woman who does not take kindly to racist stereotypical views. She gets her cousins to beat and tattoo the fake Brett with the words chosen by Cassandra. She forces her way into an audition for a new tutor and gets it before then leaving for London.
Thirdly the story of Kerrys is explored. Kerrys and her girlfriend break into Cassandra's beachhouse and stay there. Her brother upon discovering them inside, locks them in the panic room and throws a party. While, Dillon and Smoothy visit his house, they ask him to keep the diamonds (now only 14 left) at his house. When the two girls escape from the panic room, they lock her brother in there and run away.
Fourthly, Jo, who works at a 24-hour supermarket with Angelo (Jacob Anderson) finds that her new manager ("Tee" Noel Clarke) is in town. Tee has been working with Dillon and Smoothy to deliver the diamonds, but one is missing. Tee asks Dillon and Smoothy to come over to the supermarket; Dillon and Smoothy open the safe with the key (which Tee had given to them earlier), they remove the money and drop off the diamonds (which are 14, but Tee thinks there is 15). Dillon and Smoothy come to get the money, when they find Tee has betrayed them, and they rob the store and leave Tee with the 14 diamonds. Tee, however has hidden them in a Pringles box, which is then seen in flashback to show that the box is the very same one that Shannon has. Whilst Tee is about to be shot by the same woman who rescued Shannon earlier, Jo rescues him, but when he tries to run, Angelo attacks him. He is arrested by the police for illegal selling.
Cassandra returns with the last diamond and the letter; the three (Cassandra, Jo, and Kerrys) then go to meet Shannon. They put the 14 diamonds together and give it into the police and fly to New York. Whilst on the plane it is revealed that the same mysterious woman who had rescued Shannon is on the plane.