Hattie Morahan will play Beatrice-Joanna
Hattie Morahan will play Beatrice-Joanna

"In darkness, you may see him," says Beatrice-Joanna of her lover Alsemero, a brilliant man of shining virtue. The principle holds true for the play as a whole: the flickering candlelight of the Sam Wanamaker Playhouse illuminates Thomas Middleton and William Rowley's oddball tragedy. Every reference to sight sings out.

The Changeling is a play of counterfeits. Appearances prove deceptive, but they're often deliberately deployed to do so. Beatrice-Joanna (Hattie Morahan), so outwardly prim, orders the murder of her unwanted fiancé, clearing the way for Alsemero. Her servant Deflores (Trystan Gravelle), who turns killer out of love for her, is polite and deferent even as he slices through his victim's heel to stop short his escape. He takes his payment through serial rape in secret, forcing Beatrice-Joanna to fake her virginity when Alsemero tests it with a potion. In its wonky subplot, sane men play mad for a shot at a shag.

There's a fierce feminism at work in Dominic Dromgoole's production: a gritted outrage at men that push themselves – through force or duplicity, successfully or not – on women. Each grab at a dress, each arrogant advance, let alone each actual rape, is doubly repulsive here, and even Simon Harrison's Alsemero, who has every right to feel wronged, seems a bad apple at his core. One suspects his closet of potions contains some of Bill Cosby's 'medicine'.

But Dromgoole's chief success is that theme of fakery. His madmen, rattling their cages and howling at the moon, cannot conceal their urges. One fucks anything that moves. Another – hilariously – keeps bidding for freedom. Pearce Quigley's ticklish Lollio battles to keep them in check, barking like an exasperated babysitter.

The sane, Dromgoole suggests, are simply better at hiding desires and keeping motives unseen. Not Beatrice-Joanna, mind: Morahan plays her like an open book. She flinches when repulsed and undermines every lie by nodding or shaking her head. That can seem melodramatic – subtext bubbles to the surface – but there's good reason for it. In her desperation to read others, she's all eyes: sometimes bulging like comedy specs; sometimes trailing you round the room like a portrait.

That's how Dromgoole makes the two halves of this problem play – asylum and castle – make sense of each other. His characters are just as split down the middle; all two-tone personalities, saintly and sinning – as all of us are. Gravelle's Deflores, pustules down one side of his face, exemplifies that: dry humour keeps him likeable, despite rape and murder, and he's still sympathetic. Beatrice-Joanna's touch seems like his first in years. Brian Ferguson's faux-madman Antonio, Sarah MacRae's wily Isabella and Quigley's kindly jailer, who's just doing his job after all, are all equally complex.

If that keeps you thinking, with detective work aplenty, Dromgoole also hooks you in. The Wanamaker plays like a dream: murder's most foul in its half-light, yet laughs simmer throughout. Sophie Barber's strings, slip-sliding in and out of tune, and some gorgeous poetry, delight the ears as well.

The Changeling runs at the Sam Wanamaker Playhouse until 1st March. Click here for more information and to book tickets.