Hear no evil, speak no evil, see no evil. When Jimmy, 15, is brutally murdered by two hooded figures, Becky, Kurtis, Paul (Russell Tovey) Neville and the other residents of the Serenity House tower block are witnesses to the killing but fearing retribution they are too scared to give detectives any information and the police investigation is going nowhere.One year later and someone has taken justice into their own hands. Picked off one by one, the tenants of Serenity House are under threat from a mystery sniper who has also set traps throughout the building holding them prisoners in their own homes. Unsure of why they have been targeted the group put their differences aside undertaking daring attempts to escape the building. But with every exit leading to another death, will they ever escape?