The man in the mask staggers up and down the hall, bottle in one hand, between rows of Year 6 pupils. He shouts at them angrily and gestures wildly.
The children sit in silence. They have watched this character, Al Kohol, go from a gullible 13-year-old being egged on to take his first drink at a party to an alcoholic adult no-hoper. "You have just seen it," he tells them finally. "24 years of my life in 30 minutes."
Behind the mask is actor Paul Stevens, whose one-man play Time in a Bottle is touring primary schools in Devon. The current shows are funded by Devon County Council; a previous tour was backed by the Portman Group.
The messages are stark: when Al is out drinking with his mates, the ugly mask goes on. When he's back at home, off it comes again. But as the play progresses he finds removing the mask increasingly difficult.
Welshman Paul Stevens makes no secret of the play's origins. The character Al is based on his own father, an alcoholic who died 18 months ago. In his later years he got to the stage where you would see him sitting in the street. He wouldn't know where he was.
"Alcohol is such a grey area. It's not black and white like, say, smoking or cocaine or heroin. With alcohol it's all around us. Your parents drink, your teachers drink." He tells pupils from West Croft and St Margaret's junior schools, Bideford: "The reality is you will all experience alcohol. It's about treating it with respect. My dad didn't - and at the end of the day my dad died."
The second half of Paul's show is a thought-provoking workshop where he gets youngsters to do role-play, quizzes them on the facts surrounding alcohol and tests their resilience to peer pressure. Standing all 153 children in a huge circle facing away from him, he plays "spin the bottle". He strings them along that the winner will get to drink a bottle of strong lager to demonstrate its effects. But, when he asks anyone not wanting to join in to sit down, only 16 pupils actually do.
Most of these primary school children are still eager to give it a try.
Paul Stevens can be contacted at PS Productions, tel: 01395 272524.