It’s not easy being a teenager in the 21st century. Katie (aka Fish, later Bunny), the girl whose stream of consciousness monologue makes up Jack Thorne’s short play, is an exemplar. She wants to fit in – with her parents’ aspirations for her, with her school-friends, with her older boyfriend’s work colleagues, with the edgy multi-cultural society which is modern-day Luton – and she knows that her philosophy of “if you do something wrong you put it right by doing another wrong” isn’t really a creed for proper living.

It all comes to a head on a hot summer’s day. What was a trivial accident involving a boy on a bike and her boyfriend’s ice-cream escalates alarmingly. It takes Katie into places, physical and moral, which are strange and upsetting. She has to make choices; these have to involve betrayals. Neither her vocabulary nor her embryonic personality can really cope with this. Whatever she does in her future life will always be coloured by what she has – or has not – done in that steamy early evening after school orchestra practice.

Rosie Wyatt’s performance is a fast-spoken, layered teeshirt-clutching whirlwind of emotional insecurities. It is thrust at us in front of sequence of brilliantly hand-drawn black and white projected illustrations which echo the verbal journey with the townscape in which it occurs. These are by Jenny Turner with video design by Ian William Galloway. They give the show a life which, for all the bravura of the writing and acting, it does not otherwise convincingly possess.