Harry Hambridge, a struggling builder residing in London, faces a series of unfortunate events in a single day: he loses his job, his father, and his cherished pet hamster, Mouse. Upon returning home to lay his father to rest, he discovers a letter from his grandfather. The letter claims that his grandfather was the one who hoisted the flag over the GPO during the 1916 Rising, a flag that is now displayed upside-down in a military barracks in England. Tired of the ridicule that has plagued his life, Harry embarks on a quest with his eclectic group of friends to retrieve that “fecking flag” and perhaps rediscover his zest for life in the process.