During the beginning of the Chimeran invasion of Britain, Captain Buckler and units from the British Army attempted to stop the Chimera, who had already conquered the east of Britain, from conquering the west. They set up fortified trenches and tanks in and around Salisbury preparing to flatten the Chimera in a ground battle; however, the Chimera utilized Spires and infected all of Salisbury within minutes. Only Buckler survived and was found in a shell shock state near Exeter by a British squad patrolling the area. After his rescue he headed to Southern Command and was presumably present when the Chimera overran it.
He escaped to Cardiff with the few survivors of the British resistance. Buckler later participated in the Anglo-American assault on the Chimeran Tower in London. He commanded Alpha Company and died while protecting Stephen Cartwright and Task Five as they placed explosive charges on Tower Bridge in preventing the Goliaths' advance from launching a Spire attack and infecting the last of the human forces.