A teenage boy stands in the middle of the playground, arms outstretched. "Come on - you got something I want; I got something you want," he calls out to a girl.
Meanwhile, another teenage boy and girl sit in his living room. "It's a zom-com," the boy says, reading from the back of a DVD case. She likes zombie films, too, so they decide to watch it, occasionally exchanging glances at one another across the sofa.
The two relationships - one skin-crawling, the other almost cloyingly sweet - form part of a new, 18-minute film, released today by the Child Exploitation and Online Protection Centre (CEOP), a branch of the UK police that works across the country to tackle sex abuse.
The film depicts two relationships. In the first, 15-year-olds Danny and Sophie bond over a zombie-based romantic comedy. Their nascent relationship has teething problems - Danny is worried that his friends might tease him for having a girlfriend - but ultimately their mutual fondness wins out.
The other relationship, however, is different. Fourteen-year-old Chloe appears to be seeing Ash. But then she and Ash go back to a flat belonging to another boy, Marcus, who summons her into the bedroom. She obeys, but with obvious reluctance.
The problem of girls being groomed for sex has received increasing attention in England, with the recent convictions of groups of men from predominantly Asian backgrounds for exploiting white girls. But the deputy children's commissioner, Sue Berelowitz, has warned schools that it is dangerous and wrong to assume that perpetrators or victims are confined to any particular ethnic group.
Indeed, more than 2,400 children were confirmed as victims of sexual exploitation by gangs and groups, between August 2010 and October 2011. Because many cases remain unreported, the real figure is likely to be much higher.
"There's increasing concern over group or gang exploitation," said Jonathan Baggaley, CEOP's head of education. "It's the process of young people receiving something - it could be food or drugs or alcohol - in exchange for sex."
The abuse usually involves an offender befriending a young girl (or, occasionally, boy), taking her to parties, giving her gifts and leading her to believe that he is her boyfriend. Eventually, he convinces her to sleep with his friends. She believes that she needs to do whatever he asks in order to maintain his love.
Alternatively, exploitation may take place within a street gang. Here, it is used as a means of expressing power: initiation to the gang may involve rape, or sex may be a means for a gang member to pay off a debt.
"The reality of child sexual exploitation is that it's terrifying," Mr Baggaley said. "But it does happen. For many young people, if you present something that's terrifying, they might switch off.
"So we decided to look at the underlying behaviours that characterise exploitation: how people might use threats or bribes, or push boundaries, to manipulate people into what they want."
Chloe's story, therefore, is intended to highlight one of the forms that exploitation may take. The exploitative nature of her relationship with Marcus and Ash is emphasised by juxtaposing it against the mutually respectful - but not problem-free - relationship between Danny and Sophie.
"In every relationship, things aren't going to go right all the time," Mr Baggaley said. "But as long as you're being open and honest, and have shared attitudes and interests, that's the main thing. We wanted to show what good looks like."
Established in 2006, CEOP works with teachers, social workers and academics. The new film comes with a teachers' resource pack, intended to facilitate in-depth discussion of the topic.
"Young people have a lot of freedom," said Jenny Barksfield of the PSHE Association, which advises schools on personal, social and health education. "And with that comes potential to be vulnerable, as well. It's not easy tackling these issues with young people. But that doesn't mean that we should shy away from it. Young people need to be equipped to look after themselves and their own personal safety."
To watch the video and for other resources shared by CEOP on TES Connect, go to www.tesconnect.comCEOP