When Ianto Jones performed a search on Clement McDonald and the Holly Tree Lodge, a monitoring station at Ashton Down detected it and alerted Johnson and her team as to the development and the location of Clement. Johnson ordered her men to send a team to bring Clement in. (TV: Children of Earth: Day One)
Following the bombing of Torchwood Three, John Frobisher ordered the remains of Jack Harkness sent to Ashton Down where they were locked in a cell in the compound's prison block alongside the bodies of Doctor Rupesh Patanjali and a soldier who was killed in the operation to assassinate Torchwood. After Jack's immortality caused him to regenerate, Johnson had his cell filled with cement to prevent Jack's escape.
Having overheard Frobisher order Jack be brought to Ashton Down, Lois Habiba provided Gwen Cooper and Rhys Williams with plans for the compound as well as the suggestion to ambush an undertaker on his way to retrieve the body of Rupesh for his family. Gwen and Rhys succeeded in infiltrating the compound and found Jack's cell, but were caught by Johnson and her men after Gwen's disabling of the security cameras was noticed. Having tracked the van carrying Jack to Ashton Down, Ianto Jones ripped Jack's cell out of the prison block with a forklift and escaped with Gwen and Rhys. Ianto was able to free Jack by dumping his concrete cell into a nearby quarry. (TV: Children of Earth: Day Two)
As the crisis continued, Johnson continued to use the Ashton Down monitoring station to keep an eye on events. After Alice Carter called the police looking for information on Jack, the monitoring station was able to intercept the call and identify Alice as Jack's daughter. On Frobisher's orders, Johnson led a team to capture Alice and her son Steven and locked them in a cell at Ashton Down. After Ianto made a call to his sister, the monitoring station was able to track it and the new hideout of Torchwood and direct Johnson's team there. (TV: Children of Earth: Day Three, Children of Earth: Day Four)
After the arrest of Jack, Johnson released Alice and Steven from their cell but kept them at Ashton Down for their protection. After Alice convinced Johnson to work with Jack, Johnson broke Jack out of prison and brought Jack, Dekker and Dekker's equipment to Ashton Down where the equipment was set up in a huge warehouse space. Using the equipment, Jack was able to send a deadly signal that defeated the 456 and forced them to retreat from Earth. (TV: Children of Earth: Day Five)