On a cold November afternoon, Sarah Jane Smith listens to Mr Smith’s Christmas tunes from his media archive. Suddenly Mr Smith says that there is a very dangerous situation close by on Bannerman Road. Sarah calls Luke, Clyde and Rani to join her. Two minutes later they are inside her attic.
Mr Smith tells them a dangerous and possibly alien computer virus is downloading into two personal computers on Bannerman Road. Then Mr Smith shows two video feeds with an elderly woman, named Doris and a young boy, named Oli on webcam. These users can see Sarah, Clyde and Rani too but can not hear them. Both of the users are in a chat room. they have got a message with the same download link on which they clicked.
Then Mr Smith establishes an audio connection with Doris’ computer. Doris’ computer is finishing the download, a sound of metal being twisted and bent can be heard, accompanied by malicious laughter. Something is coming out of the computer. Sarah Jane talks to Doris and tells her to stay calm. She also wants to know where Doris is living. Doris replies that she is living at 54 Bannerman Road and runs out of the room. The webcam seems to follow her looking down at her from the middle of the living room. Then the video feed breaks. Rani and Clyde run down the stairs to Doris’ house.
Mr Smith now establishes an audio connection with Oli’s computer. Oli is joined by his mother Trish. Sarah talks to Oli and tells him that he has to evacuate the house, because his download will damage the computer and make it explode. Then Sarah and Luke go to the streets to meet Oli and Trish.
Meanwhile, Rani and Clyde arrive at Doris’ house. they get into the house and arm themselves with things from Doris’ kitchen. Then they see that Doris is chased by a locust made of metal. Rani hits the locust with a pan, then the locust vanishes. Clyde goes outside and tries to find the locust. When Clyde is away the locust attacks Rani and an alien intelligence takes control over her mind. As Clyde returns to the room the locust seems to be gone. Rani tells him that she is fine. they leave the house and take the remains of Doris’ computer with them because Doris doesn’t want to keep it at home.
In the meantime Sarah and Luke arrive at Oli’s house. Oli is exited to leave the house but his mother isn’t so pleased. She expects that Sarah and Luke want to harm them. When the same noise appears as in Doris’ home Trish lets Sarah and Luke into her room. A robot locust is getting out of the laptop and flying towards Sarah and Luke. Then Sarah throws water from a flower vase at the locust. The locust falls onto the ground. Luke takes the deactivated locust with him. Rani and Clyde join them. Then the Bannerman Road gang leaves Trish and Oli.
At the attic Sarah realises that there is something wrong with Rani, but can’t say what it is. Then Rani leaves the attic. She says that she wants to call her parents. Rani has no control over herself and hears herself speak against her will. She phones Ian Webster and tells him that Clyde Langer fancies Sonia Parks, which could be used to their advantage. She also gives Clyde’s phone number to Ian. Meanwhile, Mr Smith scans the locust. He tells Sarah that the locust solely is made from Earth technology. The locust device consists of various components of the laptop. The download was a blueprint of the robot, which physically created itself out of the components of the computer.
Suddenly Clyde gets a text from Sonia. She tells him that she wants to go to the cinema with him. She attached a download link for a list of films which are playing at the local cinema. Clyde leaves the attic and downloads the link. Outside he meets Rani who has a blank face. Rani knows about the text from Sonia. Suddenly Clyde’s mobile phone transforms into a locust and Clyde is attacked by it.
In the meantime Mr Smith scans the neighbourhood and tells Luke that 58 other home invasions have occurred. There are more home invasions to come, Bannerman Road is the most effected by it. Mr Smith sends e-mails to the neighbourhood to warn the people about the download link. Through CCTV cameras Sarah and Luke watch how people are attacked by the locusts. A man flees with his twin daughters to Carlton Road. Then the locusts reached High Street. People flee from the internet café onto the street. On Bannerman Road blank faced people keep marching out of the houses and walk together down the street.
Sarah realises that Rani and Clyde are not themselves. She tells them to shake the external control, under which they are, of. Clyde threatens Sarah that if she won’t stop the investigation she will become one with the Umorgus. Then Rani and Clyde leave.
Mr Smith finds out the true source of the downloads and tells Sarah Jane that Ian Webster is responsible for this.
Sarah and Luke go to Stone and Parsons, the firm where Ian works. There are a lot of people at the firm who are controlled by the locusts, Rani and Clyde are two of them.
Sarah and Luke find out that Ian Webster is working together with the Umorgus. The Umorgus wanted to invade Earth. they found Ian Webster who felt bad, because he was bullied since his childhood. At first it were the people at Bannerman Road, where he lived as a child. As a grown up he was bullied by his colleagues at Stone and Parsons. Ian wanted to take revenge and when the Umorgus asked him to work together to take control of his bullies Ian agreed to do so.
Ian doesn’t realise that the Umorgus want to control the whole world. He enjoys having control over his colleagues and being able to tell them what they need to do. He threats them as his slaves.
Suddenly Sarah speaks to Ian and tells she can understand how he feels, but that he can do so much good and that he is ruining his life only for revenge. Then Ian introduces Sarah to the Umorgus. The Umorgus tells her that through the computer virus and the locus he can control the whole world. It’s the first time that Ian hears about the Umorgus real plans. Then the Umorgus takes control of Ian. He orders him to send the virus through the whole world. After this the Umorgus wants to eat Sarah.
Meanwhile, Luke gets to the main computer of the building and hacks into its system. Suddenly an alarm sound can be heard in the whole building. Luke creates an emergency lock down and cuts down all external communication. The virus can’t be sent through the world.
The Umorgus tells his slaves to get into the security and catch Luke. Ian tries to contact several other slaves in other parts of the building, but Sarah Jane uses her sonic lipstick on Ian’s headset. A loud shrill sound can be heard all over the building. The personalities of the people return, the Umorgus looses his control over them. The deactivated locusts fall from the people’s clothes. Ian gets up and tells the Umorgus that if he had known about his true intentions, he would never have helped the Umorgus. The Umorgus then leaves Earth. Ian is arrested by the police. The police thinks that only Ian is responsible for the chaos and that he caused it with a computer virus. they don’t know about the involvement of the Umorgus.
Luke, Rani, Clyde and Sarah go back home and they see the first few snow flakes of the year. To them it’s like a reward for defeating the Umorgus. Meanwhile, Oli is playing football with his friends and Doris is going to an organised speed dating.
- Mr Smith plays Christmas songs; one of them is Jingle Bells.
- Sarah gets a call from Celeste Rivers.
- The computer virus that was created by Ian Webster attacked people on Bannerman Road, Carlton Road, High Street and all over the world.
- Stone and Parsons is a cooperate company.
- Doris lives at 54 Bannerman Road.
- Ian Webster creates the locust virus.
- Rani watches a Cheryl Cole video.