A maths teacher is on the verge of committing suicide when he's rudely interrupted: a teenage girl appears in his lounge, having picked his lock with a hairpin.
Katherine is a student at Harrison's school, but he's never taught her because she has cerebral palsy. She's been locked away in special ed classes because the school has equated disability with stupidity. She's broken in to prove she's smart; now she wants him to tutor her and persuade the governors that she should be allowed an education.
He does, and so begins the complex relationship at the heart of this thought-provoking two-hander. After Katherine goes away to college, their friendship blossoms into romance – although both try to resist it, for different reasons.
Written by and starring Athena Stevens, Schism is a horrifying insight into the frustrations and humiliations of life in a wheelchair: the teachers who won't look you in the eye, or hold the door open so you can go to the loo. The wheels that leave her hands permanently cut and bloody. Stevens gleefully explores the power dynamics of their relationship, and challenges assumptions about disability and its perceived limitations.
But above all, this play is about the power of love: how it can destroy as well as nourish.
The Park's intimate studio is a fitting space (if at times uncomfortably so) as their love affair unravels. Stevens is brilliant as witty, ferociously ambitious Katherine. Jonathan McGuinness is equally impressive as Harrison who has a convenient habit of recording his innermost thoughts on a tape recorder.
The first half is funny and moving by turns, with Stevens displaying impeccable coming timing. The second half takes a darker turn. Stevens isn't afraid to make her audience squirm and her play is all the more powerful for it.
Schism is at Park Theatre, Finsbury Park until 9 June