One Summer follows two boys from Liverpool - Billy and Icky. They are in trouble with the law, haven't been to school in months, and have made enemies within the local gangs.
Billy comes from a dysfunctional broken family - with a depressed gambling addicted mother, and a sister who hates him. Icky comes from a family of 10 children - his mother would never miss him.
One day Billy decides to try to recapture the one happy moment in his life - a school camping trip to Wales. The two boys escape with the stolen bingo winnings of Billy's mother, and make their way by train to the countryside. There they find Kidder - a reclusive drop out school teacher, who against his better judgement takes the boys into his home. The emotional bond that forms between the three is at the heart of One Summer.