Clare is a journalist working for a modern female magazine, when she's entrusted with an assignment to write a feature on the male psyche. Moments before her boyfriend Simon intends to propose marriage to her, it emerges that he has carried out two allegedly unforgivable sins; and in her very presence he carries out a third. Incensed by his conduct, Clare makes it her quest to see the world through a man's eyes for three weeks, and manages to be placed on a program where she will experience first-hand the effects of synthetic testosterone. There's just one catch: nobody must know that she's taking this volatile, potentially character changing drug. Clare's ever increasing bizarre, aggressive and apparently inexplicable behaviour leaves Simon feeling powerless, as other events overtake him, accelerating him towards an unexpected yet arranged marriage, causing them both to lose hope that their love has any chance.