Eigengrau, the new play by Penelope Skinner, writer of the critically acclaimed one-woman drama Fucked, revolves around the romantic attachments of two sets of flatmates: Rose (Sinead Matthews), an unemployed flake and Cassie (Alison O'Donnell), a feminist activist; and Mark (Geoffrey Streatfeild), a shallow marketing guy, and Tim (John Cummins), an overweight saddo working in a fast-food joint. The latter have been friends since university, while Rose and Cassie have only just met.

At the start of the play, Mark surprises Cassie by appearing in her kitchen bare-chested one morning. We gather that he and Rose have been seeing each other for a little while. The status of their relationship is unclear, however, and only adds to the awkwardness at Mark and Cassie’s first meeting as he vigorously denies the label of ‘boyfriend’ and it transpires that Rose has lied to him about her age.

O’Donnell and Streatfeild’s sparkling performances as they race through Skinner’s spot-on dialogue set the pace for the rest of the 90 minutes, which is played straight through. Mark and Cassie – and Rose when she appears in a couple of scenes’ time – are all undeniably stereotyped, but so brilliantly nuanced that they have the audience shrieking with delight.

Polly Findlay’s generous direction gives her cast the freedom to push the humour – and also the frequent palpable discomfort – in Skinner’s writing to the limit. By putting the audience on two sides of the action facing each other across the traverse stage, designer Hannah Clark cleverly ups the ante of both comedy and awkwardness as those sitting on one side of the theatre see the amused or shocked expressions of those opposite.

The relationship that develops between Cassie and Mark, and ultimately Tim and Rose, and the uncomfortable truths that are uncovered along the way raise some interesting points about how what we want is not always compatible with what we think we want. Cassie has greater depth as a character than any of the others, and as a result, her journey, characterised by a massive emotional and ideological fall, is the most affecting of the play. Particularly powerful is the way Skinner, Findlay and O'Donnell take us along with Cassie, so that her fall is also somehow ours.

Less successful is the message behind this fall, which is muddled and feels undercooked intellectually. Ideas and motifs from ancient Greek tragedy are thrown in, presumably, as a commentary on the problem of sexual ethics at the play’s heart, but it’s unclear what point Skinner is trying to make here and the dramatic climax is at odds with everything that’s come before.

These flaws are fortunately not serious enough to take anything away from what is an hysterically funny perspective on 21st-century relationships. By the way, lest you haven’t your dictionary to hand, the title is a noun that refers to the colour seen by the eye in perfect darkness.