When Johnny, an unemployed hipster, stumbles across his latest passion project, he becomes obsessed with baking the perfect loaf of sourdough bread. As he delves deeper and deeper into his bread making he clashes with his girlfriend, Mary, who just wants him to get a real job. When Johnny discovers that his local supermarket is holding a contest for the best loaf of bread in Ireland, he becomes unhinged, taking on the persona of a mad scientist which results in devastating consequences.