In Exeter, 21-year-old Scott has been partying so hard he can't remember who he's slept with. When his worried mates bring him in for his first STI test, he gets a sobering wake-up call. And will it be double STI trouble for brothers Robbie and Tom after a season of festival fun? In Leeds, 25-year-old Chloe is facing the prospect of her second STI, ex-army recruit Carl has heard rumours that an ex may have given him chlamydia and 17-year-old Matthew has got worrying symptoms.