Grid Iron's Mayflies, a site-specific theatre production marking the company's 30th anniversary, is a compelling yet uneven adaptation of Andrew O'Hagan's novel. Set in a former engineering works in Leith, the play unfolds around the audience, utilizing the space to create an immersive experience. The first half, focusing on the friendship between Tully and Noodles in their final years of high school, is a celebration of youth and potential. The actors playing young Tully and Noodles are particularly compelling, brimming with excitement and intensity. However, the second half, which telescopes forward decades to Tully receiving a terminal diagnosis, feels like a wrench rather than a progression. The script seems more convinced by youth than experience, and the profound questions of life and death posed by the second half feel almost workaday. Despite this, the performances save the show, with older Noodles narrating the drama with pathos and Graham Mackay-Bruce retaining some of Tully's rakishness into adulthood. The intensity of the human drama ultimately makes this production worth seeing, despite its structural issues.