Free Fire centers around an arms deal that goes spectacularly and explosively wrong. Justine (Larson) has brokered a meeting in a deserted warehouse between two Irishmen and a gang led by Vernon (Copley) and Ord (Hammer), who are selling them a stash of guns. But when shots are fired during the handover, complete pandemonium ensues, with everyone at the scene suddenly thrust into a heart-stopping game of survival.