England, mid 1950s, Wormsley Common, a run-down and tough area of Outer London. The Wormsley Common Gang, who took their name from where they are growing up, are a group of rough and disrespectful young boys whose ages range from nine to fifteen years of age. Their favorite thing to do during the summer is pull pranks and every day they gather in an empty lot where a street full of houses used to stand. The houses were destroyed during the blitz. Only one house remains. It survived the German bombs during the Blitz in World War Two and hangs perilously on the edge of the empty lot where the boys meet. The owner of the house is a Mr Thomas, a solitary elderly man who, in his prime, worked in construction; Mr Thomas keeps to himself and doesn't like the boys; they nickname him rather unkindly, "Old Misery".
Until recently a boy called Blackie was the leader of the gang. Their newest member, Trevor, comes from a far more affluent background than most of the boys, but his parents have fallen on harder times recently and have been forced to relocated to Wormsley Common. The rest of the boys tease him for his "posh" name. However, he seems to carry himself with a toughness that they respect and they don't make him carry out any humiliating hazing ritual, letting him join the gang immediately. They call him "T" because it sounds tougher than Trevor.
Trevor is late to their daily meeting and so Blackie interrogates him. Where has he been? What's he been up to? T explains that he went to see Old Misery and had a tour of the old house. He says that it is beautiful. Blackie doesn't think that an appreciation for architecture is quite becoming for a member of the Wormsley Common Gang, and tells T so, but T responds that he has been planning a prank. The visit was simply research.
T's plan is simple; destroy the house from the inside out so that they managed to do most of their damage before anyone passing by sees them and puts a stop to it. Once they have destroyed the interior they will finish off the job with the exterior. It turns out that Mr Thomas is planning to go out of town for the upcoming holiday weekend. They can destroy the house then. Blackie hates the plan but is outvoted by the rest of the boys who all want to participate. Blackie is hurt by their lack of loyalty towards him but does have to admit that once word gets around their gang's reputation would be bolstered. He reluctantly agrees and gives leadership to T.
The boys meet the next day. This time Blackie is late and can already hear the destruction going on inside the old house when he arrives. Walking through the house he is impressed with the organization of its destruction. The boys are methodically destroying everything from floors to banisters, whilst leaving the walls where they are. T is lord of all he surveys, listening with joy to the sounds of the architectural carnage around him. He orders Blackie to start breaking up the bathroom.
When the other boys leave at the end of the day, T takes Blackie aside and shows him what he has found; a mattress stuffed with Mr Thomas' savings. T doesn't want to steal the money; he wants to burn it. Blackie asks him why he hates Old Misery so much, and T replies that he doesn't, really. Love and hate aren't real emotions. They don't matter. Things matter and T likes destroying things. They burn the money note by note and then race each other home.
Day two of the destruction; the boys flood the house before Mike rushes in to tell them that Mr Thomas has returned home early. Another boy, Summers, suggests they leave before they are caught. He starts to mock Trevor again by using his given name but Blackie shoves him hard, showing that he is in full support of T. Blackie is leader again. He sends Mike to the outhouse and instructs him to lock Old Misery inside. As Mr Thomas arrives home, a boy runs up to him to tell him that another boy is stuck inside the outhouse lavatory. As he opens the door to free the boy he is shoved hard and locked inside.
The boys tie the wooden support struts of the house to a tuck that is parked just outside. The following morning when the truck driver pulls out of the spot, he unwittingly pulls away the supporting struts as well. There is a huge crash and rubble rains down everywhere. As he hurries to see what has happened he hears Mr Thomas' shouts from the outhouse and goes to free him, just in time for him to see the fragments of his life disappearing into the rubble of what used to be his home. The driver laughs, somehow finding humor in the spectacle of the situation. Mr Thomas' anger only makes him laugh harder.
