Hans Christian Andersen had his secrets. By day, a revered children’s writer — the Greatest of Danes; by night, a repressed brothel habitué. Whitewashed as his legacy has been, it’s unlikely he kept a pygmy woman prisoner in a mahogany box, passing her words off as his own, as Martin McDonagh’s disjointed new play portrays.

Part question-mark over artistic identity, part surreal metaphor for colonial guilt, “A Very Very Very Dark Matter” is a very, very, very strange play. It finds Jim Broadbent’s airheaded Andersen living in a treehouse-style loft, taking credit for tales churned out by his one-legged, short-statured Congolese captive, Mbute Masakele (Johnetta Eula’Mae Ackles). He calls her Marjory — unable or unwilling to wrap his tongue round those ms — and feeds sausage strings through a hole in her three-foot-square box.

There’s some literary logic behind this grim flight of fancy. Andersen’s stories are rife with self-doubt: ugly ducklings, exposed emperors and writers outdone and undone by their own shadows. In a characteristically campy turn, Broadbent plays him as a tone-deaf bimbo, reveling in his unearned reputation as he flicks through his fan mail, and dispensing rambling racist tangents at public readings. He’s a fraud, and a foul one, sadistically squeezing his creative slave back into a box he downsizes, one inch at a time.