A reasonable response to the men's rights movement, Angry Alan follows the radicalisation of Roger (Donald Sage Mackay), who finds the answer to his alienation in the online rants of the titular activist. Roger, having lost his well-paid job, his marriage and self-respect, promptly rips the rest of his life to pieces.

The ugliness of men's rights activism, unfortunately, does not make for a serious drama: Roger's parroting of the party line is risible and his tragedy – never realising his own privilege – is engineered by the abrupt arrival of a son in crisis. MacKay does his best to make Roger amiable, but Penelope Skinner's script is too willing to present the stupidity of the activists without answering its contradictions or digging beneath the simple equation that perceived male failure leads to acceptance of a frankly incoherent anti-feminism.

Yet the drama fails to rise above Roger's naivety: the tragic finale is forced, partially because Roger is telling the story and cannot see beyond his own concerns, and the serious investigation of a toxic yet potent movement is reduced to a series of shocked, mocking laughs by the audience. A vital matter is reduced to an isolated and personal tale of foolishness, made entertaining by MacKay's performance and Skinner's culling of men's rights activism talking points.

Underbelly, Cowgate, until 26 Aug (not 13), 3.20pm, £13–£14 (£12–£13).